That is one of my favorite car shopping activities. Just some general tips bc a lot of good things have been said.
1. Always do your homework and research. You should definitely know (or have a good idea) of what you want and what price range a car typically sells for before you shop.
1a. You should also have a good idea whether you intend to buy new or used.
2. You should do a thorough financial analysis of your cash on hand, current expenses, and include a (sketchy at least; detailed is better) projection of your expected monthly payment and expenses with this new vehicle.
3. Storage; you have to have a place to put it (or plan a place to put it)
4. Car's expected life expectancy; How long you plan on keeping it all things being equal.
5. Look at an online price comparison like edmunds. It will give you a great start in knowing what an average price for a car should be.
6. Start locally and get a first price. Never, (repeat) never settle on a car on the first visit (although sometimes luck will have it that the first dealer will end up being the place you buy from....you won't know that until you've shopped around though).
7. Listen to the sales person's pitch, then haggle (negotiate) intelligently. Realize this; A dealer already knows his bottom price, and if you come in below it then that dealer will not sell you the car.
8. Shop around. A better price/deal/car can always be found. Never negotiate with incentives or finance rates. You want to negotiate with the selling price; incentives will come automatically (if its offered). How sweet a deal it could be to get the best price possible and incentives as a bonus.
9. You also need to figure out who will finance your deal. This should be a part of your financial analysis before shopping. Do not allow a dealer to finance the car without checking out the specifics. You could potentially get ripped off if you do not find out all of the aspects on financing before purchasing a car.
10. When you find the best opportunity, act! Waiting or indecisiveness will cost you to lose a good price or car opportunity; However, if you are not sure that you want the car or if its the best deal then move on and continue shopping.
It can be fun; as long as you maintain control. Regardless of what is said by anyone, ultimately you will make the decision whether to purchase.