Since becoming an administrator, my participation in voting on AFD has declined. I am more into the closing AFD debate business now. Still I do vote sometimes, so I will put down some of my thoughts on the matter.
It is common to divide AFD regulars into two camps, deletionists and inclusionists. There is also an in-between camp called mergists. Some people label themselves as such, and have formed associations. Very many others have not, and neither have I. Well, I have joined this association. I think that the vote should be decided on the article and its subject (in a few select cases other reasons may apply, such as a third renomination after two clear keep debates). It is a bad idea to feel for instance that "I cannot vote delete on this, I am an inclusionist, and it would be hypocritical of me to vote delete!". Don't make votes based on how you label yourself.
The factionalism caused by this splitting into two or three camps is not so good. I have seen users oppose the adminship nomination of excellent and good-faith contributors, simply because they don't agree with their VFD votes. This bothers me (see my admin criterion).
There are nonetheless some classes of articles which often come up on VFD, and my view of them is this:
Schools edit
An amazingly contentious issue, perhaps the most contentious issue between the deletionist and inclusionist camp, and the wisest thing to do might be to stay out of the debate. My contribution to the "Arguments" section of the debate has been to add a arguments-for-merging section. Schools may be notable in the community in which they are located, but few people care about them if they don't care about the community, so merging the schools in some form is the best way to provide context unless the school is outstandingly notable.
Fancruft edit
Perhaps the VFD on the first article I created as an anon influenced me... I am fairly liberal with handing out keep votes or merge votes on pretty much all fictional characters and items from books, comics and games. But also, fancruft is usually of interest to fans... and there are many thousands, often millions of them. If they are interested in reading this, by all means let them. I do have a line drawn on this subject however: Fanfiction is usually not notable (won't be of interest to most fans). Also, articles about a single event in a book or cartoon is not really encyclopedic either since I cannot expect fans to really be interested in this level of detail. Wikipedia:Votes for deletion/Plaque conspiracy is a debate I started over a joke in a cartoon. WP:FICT is one guideline which I fully support.
Notability edit
I don't subscribe to the notion that "non-notability is not a criterion for deletion". Had this been the case we might as well have articles about every person in existence. The question is where to place the bar. Now I will admit that my personal bar for notability is not really fixed. On a good day I might set the bar low. On a bad day I might set it high. In general though one question to ask is: "Will the article be of interest to casual readers?" Not an easy question to answer...
Hoaxes edit
Delete. Get rid of them. These things compromise the integrity of the encyclopedia. I think even most of the hardline inclusionists agree with this one...
Bands edit
WP:MUSIC is one guideline I follow here, but that is a guideline, and a band might be notable even if it does not meet the criteria set there. Therefore I opposed the close CSD proposal which called for the speedy deletion of bands which did not meet them. The notability should be discussed on VFD.
Substubs edit
There are some articles which are really short, without much more e.g. than "xxx is a yyy in zzz". The trouble with such articles is that they are not really very useful. People reading such an article probably knew basic info like that already. Should such things be deleted? Not sure, but it is clearly more fruitful to make a minor non-trivial expansion (such as adding the city's population) than trying to nominate it for deletion.
With that said, I have removed about 300 articles on uninhabited islands in the Malidives ("X is one of the uninhabited islands in the Y atoll") by converting them to redirects to the atoll.
Some relevant principles are of course WP:CSD A1 (no context) and A3 (no content).
Conlangs edit
Articles on constructed languages have started turning up on VFD sometimes, and when I vote on them it is usually "delete". I just don't think that an artificial language, made by a very small group of people, used by virtually nobody, and unknown to just about everyone else, merits inclusion in the encyclopedia. There are very few constructed languages which are notable, Esperanto being one of them.