I eventually got a divorce at 30 (unrelated), and I had some great sex for a while but then got married again. While, I love my spouse, I think back on those moments of freedom and wildness often. Wish I had more memories of them.
Some tips (from the person who started late): Don't do one nighters - they're just not memorable long-term. Don't do it drunk - it dulls the memory. Don't do it just for the sex either - it's way, way more enjoyable when you're really into someone. And, don't waste time with people who have no passion or intuitiveness. If they can't kiss well or seem to lack interactivity, it's probably not worth it, no matter how much they may want you.
Nowadays the only way I can have intimate relationships is via prostitutes; however I don't visit them often as I can see through their acting, for once I would like to have an intimate relationship with someone who is truly into me, but then I am 33 and my libido is fading (yay!) I know that I will regret not having sex in my 30's and 20's in my 40's but I feel powerless.
As far as how to find them, don't use dating services. It's way too hard for 'normal' guys to compete. Women get so much attention on those services that it boosts their expectations, and they become more selective. Instead, you have to go to the places that they go.
As for looks, put it in context. Unless you're in one of the high male areas (where competition naturally forces men to up their game), most men are pretty average looking. If you look around, I'm guessing you'll see lots of men who are in the middle. That's your baseline. And, if you can get 5-10% better, then it's remarkably more effective.
As a man, if you can get the basics right (personal hygiene, good clothes), you are already in the top quantile. Bummer about the height, but there are also women who are not very tall.
Actually, I its the shorter women who have higher standards for male height, the most "harsh" rejections (due to height) have come from short women.
Taller women have been friendlier/more polite but at the end of the day I still get rejected.
So if you're 16 and want to have sex with someone who's 16 the only certain advice I can provide is you're not likely to stop wondering what it would have been like any time soon, and over time the odds very rapidly reach zero (roughly by the time you graduate HS?), so get out there while you can ... while avoiding diseases and pregnancies. Of course seeing as older, smarter, and far more experienced versions of yourself repeatedly manage to fail to avoid diseases and pregnancies remarkably often, maybe forever wondering is better than forever herpes/hiv or forever having kids while you were still a kid yourself.
I have heard of couple's coming to an arrangement where the husband (it always seems to be the husband) goes once a month.
Similarly I have met divorced men who opt for brothels in place of pursuing other relationships. This decision typically seems to come after an expensive divorce when they do the math and realize that it may be cheaper to have sex with a parade of paid professionals Vs getting into another serious relationship and losing half their stuff again.
This is probably exactly why brothels are highly illegal in most places. Can't have people disrupting the social order...