Newbies edit
Most people first come to Wikipedia through a search engine, after looking up something for a research project, and finding that Wikipedia has a better collaboration of information than anywhere else. Most new users, therefore, will use Wikipedia for some time before ever contributing anything. I know that on a personal basis, I at first didn't realise that I could edit Wikipedia, thinking that it was a real encyclopaedia that couldn't be touched. Indeed, most people who use Wikipedia never make a single edit.
First edits edit
The first edit by a new user is usually to fix up some small thing in an article which they were researching. They might know a bit about the article, but not know everything, and then see something and know automatically "that's just wrong" so they fix it.
Typical first reaction edit
Most new users have their first edit reverted, often with a comment of "vandalism", which some older Wikipedia users believe is implied purely because of a lack of edit history. Some older users may even go so far as to place warning signs in a user's talk page implying that their only reason for being on Wikipedia is to destroy everything, something that is a very common reaction. Luckily, most new users don't even realise that they have a user page, and hence don't ever see that comment.
Making them earn it edit
Some people are of the belief that if they "do the time, do the crime", and hence, after being incorrectly accused of vandalism, they will then actually do something bad. They might start blanking pages, or putting nonsense on pages, or making up stupid joke pages, or attack pages, attack individual users, or even do perhaps the most dangerous thing, which is to make subtle edits of pages that are not noticed for a long time, such as stating quite happily on a biography article that someone was once thought to be a suspect in the JFK assassination. Such people become vandals if for no other reason than to react to the hostility that they originally received. They see no reason they should stop their behaviour, since their earlier genuine edits resulted in nastiness. They may even see themselves as crusaders trying to right the wrongs of Wikipedia's biting of newbies.
Creating their first article edit
There are various reasons why a new user might create their first article. It might be because of being "bitten" whilst trying to edit an existing article, it might be because they followed a "red link" to an article that doesn't exist, with the message asking them to create a new article, it might be because they tried to look up a topic and there was nothing about it, or it might just be so as to have their own space to write. Whatever the reason, the vast majority of first articles created by genuine new users are good faith attempts at writing an article.
Typical reaction to creating their first article edit
A proportion of Wikipedia editors, most of whom are granted admin status, are self-proclaimed "Vandal fighters" and, as part of their mission statement, they believe that they should scan for new articles created, especially by new users, and put a nomination for deletion notice on the article. Some "Vandal fighters" will even go so far as to speedy delete the article (or even in some cases delete it outright) and may even couple this with a warning on the user's talk page, or even a block. Thus a good faith attempt at an article can be nominated for deletion 1 minute after initial creation.
New user reaction to AFD notice edit
The new user reaction to having an AFD notice put on their first ever article just minutes after creation is one of hostility. They may remove the AFD notice, change the votes from "delete" to "keep", vote "keep" several times themselves, create new accounts so as to vote keep several times, or call their friends to create new accounts to vote "keep", these being "meat puppets". The end result of any of these actions is that the new user has their article deleted, with increasingly nasty comments made towards them. Some new users give up and don't bother coming to Wikipedia anymore after that. And even if they had not tried to manipulate the vote, they will still get treated with disdain and talked down to.
Response to the well behaved new user in AFD discussion edit
A small sample of new users are actually able to tolerate the torrent of abuse that they are subjected to and work politely and respectfully to make the article better. A handful of these users actually have the article kept, but the vast majority find their article deleted anyway. Thus it takes a lot of effort for them to want to keep using Wikipedia, but a few do, and they keep plugging away making new articles anyway, until finally one is accepted or passes an AFD vote.
The new user who is not really a new user edit
A lot of people who have been blocked end up coming back to Wikipedia anyway in another form, which is often referred to as a sock puppet. They might have a new IP address, or make a new username, or otherwise pretend to be someone that they are not, so as to wreak havoc. This is very difficult to detect, and is the entire reason people are so hostile towards new users. If new users were made aware that this is the reason they are treated so badly, then it might go a long way towards them understanding and accepting it, and hence not retaliating and not quitting. It would improve both the perception of Wikipedia in the outside world as well as the quality of edits.
The vandal/troll/attacker edit
A section of the community believes that the sole purpose of the internet is to destroy it. Such people are sometimes called computer hackers, but they can also be people with little or no computer knowledge who instead have social knowledge of how to disrupt systems. Such people may come to Wikipedia with the sole aim to disrupt it, from the moment that they first come. Such people may create 20 articles with almost identical names, saving the contents on their computer, knowing that the articles will be deleted, but also knowing that it is easier for them to create the articles than it is for them to be deleted. Such people go to great lengths to try to disrupt Wikipedia, and may use 100s of IP addresses and have 100s or 1000s of friends who assist them to do this. They may even write about it in blogs or web forums or their own personal web sits boasting about their success in disrupting Wikipedia. These are people who will be extremely happy to see their articles deleted, and see it as an achievement. They might aim to see people attack each other. These are perhaps the worst form of Wikipedia destroyers.
Advice for newbies edit
As a new user, I would advise them to begin by editing articles that already exist, making small edits such as fixing spelling and grammar. When the change is more significant, try to open up google or some other search engine, and try to insert a web page that can back up your claim, then insert that web page in to the article for verification. Do not be upset when your edit is reverted. Also create an account as soon as possible and fill in your user page (at least briefly) to demonstrate who you are and why you are using Wikipedia. Once you have done a few edits, then think about making a page, but make sure that the page is really needed. If it is a red link from an existing page, then that is a good sign. Otherwise, check out the criteria for notability. Simply think to yourself - would you see this in Brittanica? If not, then don't add it. Do not worry about other pages that you think should be deleted too, and your idea being similar to them. Two wrongs don't make a right, and in fact there might be other reasons not obvious to you as to why this other page was valid. Only after you have had a number of articles approved (not deleted) should you consider making a page that has not been requested. And when you do make a page, on your first edit include references. Use google again when writing the article. But don't just copy and paste! A good idea is to get 3 or 4 references and then combine their knowledge in to one article. Also include the references that you used at the bottom under "External Links". Also, avoid the temptation to make silly articles, or articles about you, your friend, or something you like that you know nobody else has heard of. It is tempting, but if you do it then you are more likely to be looked down on. Also, if you are mistreated, then talk about it. For example, if you are wrongly accused of being a vandal, write in Wikipedia_talk: Vandalism about why you think it was wrong. Whilst the individual person might not be able to listen to reason, the general community might be. And remember that the majority of users started off in the same way as you did, and hence they can understand your predicament. The official policy of Wikipedia is actually to treat newbies well, and to assume good faith WP:AGF with regards to their attempts at making a new article.
Advice for how to treat newbies edit
Unless newbies are obviously here to disrupt Wikipedia, always try to assume good faith. If you could imagine that an article was made as a good faith attempt, do not nominate it for deletion. Instead, put a tag to clean it up, and then write a notice on the user's page advising them why you think that they should tidy the article up. Give the article a month and then if it is not improved, then nominate it for deletion. Also don't use templates for accusing users of things. If you are going to accuse them of vandalism, go to write to them why you think that they might be vandalising. Impersonal accusations are very unsettling for new users, especially if they are untrue. The exception, of course, should be obvious attacks, such as blanking a page and replacing it with "John is an idiot". In such cases, the best that can be done is to assume that the user didn't realise that they can't do that. But the biggest and most important thing is not to be so hasty on nominating for deletion. Only speedy deletion candidates should be nominated for deletion immediately on creation. Those only worthy of AFD should be given a month to see what happens with them, especially if made by new users.
Advice for treating people generally edit
Wikipedia is, for the most part, a place of intellectual snobbery and is a full of all of the markings of an "old boy's club", where certain sections feel superior to others, try to ensure that everyone does what they are told, and look down on others. Thus an awful lot of bullying takes place on Wikipedia, in the form of AFD "discussions", Wikipedia talk on various topics, and especially on users' talk pages. Half of talk messages will be in some way complaining about you or bullying you. One thing that we all should remember is to try to write as many positive notes as you possibly can. Write to people's talk pages and say "well done", and if you must criticise, try to make it as constructive as possible. Whilst conflict is unavoidable, and there are different views as to whether conflict should be avoided or alternatively to gang up and attack the person who disagrees with you, you should always remember that that could be you that is being treated like that, and treat them accordingly. Remember that in the end people will be unfair, policies will be unfair, Wikipedia is unfair, and Wikipedia is in the end a private business that runs itself however it so pleases.