If she’s actually just waiting for you to finish, that’s not a great sign: It means she’s not enjoying sex—and, likely, nowhere near getting off. I’d start out by asking her what positions she likes best, how she’s the most likely to orgasm, and what type of sex she enjoys the most. If sex is something she’s doing just for you, then she’s probably not even thinking about her own enjoyment.
If that’s the case, it’s not bad to have a few rounds of “experimental sex” where you try different things and ask for feedback about what she likes. Sure, that’s not the hottest thing in the world, but it could help you improve your technique for the future—think of it as practicing some drills before a big game. Something else you might want to try is focusing more on her clitoris. Women need direct clitoral stimulation in order to have an orgasm, and the act of sex doesn’t actually provide that stimulation for many women.