Congrats on the idea to purchase a new car! I bought mine last January...so here's my advice. Definately do your homework. When you walk into the dealership, whether new or used, have an idea of what type of car you want. Know how much you are willing to spend. Know what type of features you want the car to have and find out before hand if they are INCLUDED in the original price of the car. Before you go into the dealership, check out their website. Most websites allow you to build the car you want online so you can see what it will look like and know an estimate of the cost.
Advice while in the dealership....if you know nothing about cars, make sure you take someone with you who does. You know that the dealers can tell when you are clueless, and they will try to persuade you to add on features that you really don't need. Oh yeah, and the person that does know about cars also can help you nogotiate the price. When I bought my car, I did all the talking with the dealer about what I wanted and didn't want--my dad did the nogotiating thing with the finance guy (worked out really well too, cause i got lots of extra accessories for free AND i got the car for LESS than the sticker price
). Anyway, that's just my $0.02. Good luck and don't forget to do your homework!