You gringos make sex seem so difficult.
1) If you are afraid you won't last, rub one out before you start. Give yourself about 10 minutes recovery time.
2) If you are "out of practice", don't expect to last too long, anyway. Your pipi gets excited if it doesn't play with something other than your hand/fleshlight very often. #1 helps with this.
3) If you thrust too fast you will end just as quick. Pace yourself, young padawan. She's already naked, unless you fail horridly, she's not going anywhere. Enjoy the moment!
4) Don't bore her to death with a single position and don't forget you have hands. Cheat the system by sensually/romantically changing positions. What she doesn't know is that you are giving your **** a breather. Maybe she does? Who cares.
5) Talking dirty gives you an opportunity to not only slow down a little bit so you can get close to her ear and whisper/talk sexy/whatever, but can give you insight if there's something in specific she wants. This ties in with #4.
6) Everything Smash said. All women like different things. Find out what she likes and roll with it. Don't be prude and keep an open mind. You only live once and the worse thing that can happen is you just don't like it. Express your own likes and dislikes, too. Don't be shy cause you are saying dirty things. You both are buck naked and about to have all kinds of fluid all over the place...WTF does it matter what vocabulary you use?