Friends or dating
Set the precedent that people who are awful to your friends are people who don't get to see you naked, and your life will be the better because of it.
It's difficult to meet people you're romantically interested in beyond an already-defined circle, and outside of your city's queer scene, most people you run into are likely to be straight.
This rule is almost never stated or enforced among queer communities.
If you're gay, you will almost inevitably date a friend's ex at some point.
Set aside time for each of them and honor it — don't drag your lover along on girls' night out (not even if your lover is a lady; queer chicks are 4. Don't ask your man if you're prettier/smarter/better at Scrabble than his last girlfriend.
Don't do this ever, but especially not if his last girlfriend is the person you're going rock climbing with Sunday.
Search for friends or dating:
Even if you meet someone to whom you think you have no previous connection, a 10-minute conversation almost always reveals that she went to high school with your college roommate, used to be on a volleyball team with that girl from your book club, and had a six-month stand with your favorite barista.