Competition tips & decorum

I've just entered my first two competitions, and am wondering about the general do's n don'ts of the competition world. Please jump in with any general advice or observations, and I have a few questions herein.

Are portraits generally accepted in open competitions, or just in portrait competitions?

Is it better to start locally and expand upon local wins, or just apply wherever, or apply based on a perceived "fit" (where you look at past winners and assess whether or not you're competitive with that group).

What do you think general criteria are for competition winners? Sometimes looking at the top three or five, I can't really tell if it's skill first, composition second, style third, or what. Maybe it depends on the judge?

After the top 3, in a national competition, are the special and honorable mentions of any value? Sometimes I think I prefer the honorable mentions to the "winners," and I almost always prefer People's Choice over the winners. Do people notice the "mentioned" category?

How does one parlay a win into something better? Are there galleries or agents or clients scoping these things? Can you use it to approach Artists' Magazine for an article, for instance? Send it to your local paper for PR?

If you don't win, can you resubmit the painting to another competition? What if you do win? Can you submit the same painting to competitions over and over (if the rules don't prohibit it)? What is considered bad form?

Do you paint things specifically for a competition, or do you just notice one's coming up and then send out your best work?

Are there any warning signs of a shady competition?

Thanks everybody!
Lisa