New Yorker here, we have every type of club, lounge, bar, boat, rooftop, hidden loft and dancefloor you can think of. Here's my take:
Pregaming (drinking before heading out) is actually bad advice. You'll become sloshed sooner which means you'll get sick earlier, or ruin your chances with a romantic hookup because of your slurred speech. If you want to save money, a flask in your bootleg is a much better option.
The early bird gets the worm. When a club first opens, you'll be surprised at the female/male ratio. It can sometimes be 70% female. It will stay that way for a couple hours, then dip drastically as popped-collar dudes start showing up en masse. Not only that, a lot of clubs have discounts when you arrive early. So show up early if you want to have an easier time socializing.
Know when to fold. Going past the fold time is the nightclub equivalent to "chasing the flush" in poker (look it up). Whatever scenario you're having just before the fold time will determine the rest of the night. So if you're already flirting or making out with someone by the fold time, you're good. If you haven't had any luck by the fold time, do not order another drink or try to hunt for more romantic prospects, just leave and get a slice of pizza, and go home to sleep. 9 times out of 10 you will NOT meet anyone new. Trust me. If you "chase the flush" you'll typically waste more money, come home empty-handed, and have a hangover. The fold time is usually 2-3 hours before closing time. So in L.A., their closing time is 2am, so their fold time is about 12 midnight. In New York, the fold time is 1am because the clubs close at 4am. It sounds early .... but notice the packs of men, in groups of four, roaming the streets at 1am, saying "where's the party at" whereas at that exact same moment hundreds of women are hailing taxis to go home. Don't chase the flush.