DarK SagE, if you're a fair conversationalist, just take her somewhere with a nice but casual atmosphere for dinner and drinks (I don't know how old you are).
If you're not particularly good at making small talk, take her somewhere that you can interact, but also be occupied with something else for part of the time...arcade, zoo, movie (not usually the best though), bike ride in the park, etc.
Just make her feel comfortable with you so that she'll want to do it again.
.paldo, forget the $600 watch. Giving a girl an expensive gift like that is just a good way to find out if she likes expensive things, not whether or not she likes you! I have never seen a relationship work out where the guy starts out by giving expensive gifts. If that's what she's looking to you for, she's not the one for you.
Take her window shopping sometime and remember something that she seemed to really like, but that's not that expensive. See if she appreciates the thoughtfulness of it, not the price tag, and you may be a winner.