I think there is an auto featuring program for popular/uploaded templates. They have already approved the picture so as long as the words you use don't trigger any of that programs negative criteria it goes through automatically. Most of my original memes get anywhere from 6 to 18 views before featuring, so somebody is looking at them and unless I share the link it has to be mods. My guess is only a few of them have final say about releasing a new template, otherwise some of the mods viewing them would have no reason not to release it. Now I understand why they want to view original templates first. Sure the words in the meme might be fine, but if somebody was to use pornography or something obscene in other ways. Then imglfip let it get featured on their website with their tag on the bottom of it. It would make their site look bad and this site tries very hard to remain family friendly.
So I can see their point on that stuff, it's not their fault that people would try to add the image of a p**is or whatever onto a meme so that they have to check them all for stuff like that. I'm sure if we saw some of the stuff people try to submit we would be thankful that it didn't make it through.
Another factor is of course how many memes are being submitted in day, if there is only one mod and he has a thousand memes to look at I understand how that could take some time as well. I think that might explain why certain days are better than others, either there are less memes submitted or more mods that day to check them.
However it can be very frustrating when you submit something early in the morning and it doesn't feature until late at night. We all like to get and reply to comments on our memes, and you only have so much time when something features to get enough, views, comments, and upvotes in order for it to move up the hot pages at all. I try to make myself delete them sometimes and try again but I hate doing that and it can hurt your featured percentage.
The only thing I can say for sure is that it happens to everybody equally and nobody gets special treatment. Sure it would be nice if we all got early release times and decent spots on the latest thread, but there are simply too many of us for that to be possible. I wish I knew more about how it all works, most of this is just educated guesses based on my time around here. As time goes by this site does make improvements and a little something here and there gets better as we meme along.