Ok. You said you have some issues with your body? Is it a body-size issue (weight?)? If so, I want to tell you that if you're on a date with a woman, she's already accepted your body (or already feels aroused by it - not all women want a buff hard body), so no need to worry about that during intimacy.
Here's my take on what makes sex good or "bad" :
good sex - the man is very passionate (kisses a lot, rubs my body a lot, shows me by his kissing, fondling, etc that he thinks I am incredibly sexy), he does tend to take charge - there's not much worse than a guy who is expecting you to make all the moves, is firm without being too forceful, makes sure I am aroused and possibly already have at least one orgasm before he enters me, takes a lot of time on my breasts (!) - kissing, sucking, feeling, etc, is at least a little vocal - if you're self-concious you don't need to talk or make a lot of noise, but it's awful if you can't even tell when a guy cums because he makes no sound at all.
Bad sex - the guy acts like I could be anyone, he doesn't pay much attention to my body, he is in and out quickly, he's too rough (some roughness can be fun, but if it leaves bruises, it's too much for me), he expects me to make all the moves.
You sound like a sensitive, in-tune guy, so i'm sure you'll be a good lover when the time is right. Just don't worry too much about it. :)
