Shopping for a new car is a heady feeling. If you are like most people, you're going to get caught up in the emotion of the process, forgetting your head for your heart. If you've researched car buying at all, you've read all about car-buying traps; those little tricks that dealers use to get you to spend more than you'd budgeted for. But what about car-shopping traps? Before you ever start to negotiate, there are things that you need to consider.

1. The Price

You've decided what you can reasonably pay per month for a new car. Let's say that you've settled on a payment of $300 per month. Ask yourself if that amount is pushing it. If you failed to consider the costs of car ownership, you very well may have gone over your budget before you started looking.

Think about the extras that you'll be paying for based on your daily driving. A full tank of gas, on a moderately-sized vehicle, will run you about $30 per week at today's prices. That's $120 per month. Your car payment is now $425. Insurance, on average, is $70 per month. Your car payment is now $495. Are you going to take your car to be washed every week? Then you'd better tack on an extra $32 per month. The $300 car payment you envisioned has now ballooned to over $500 per month.

2. The Down Payment

Don't go to any dealership before you decide how much you will be putting down. In days gone by, a 10 to 20 percent  downpayment  was the norm. Today, zero-down options are taken advantage of far more often than not. You know that your car loan is upside down as soon as you drive off of the lot. It can take years to build equity in your vehicle. The more that you put down, the sooner you will break even on your loan.

Don't let the dealer talk you into putting more or less down than you budgeted for. Don't tell the dealer you only have a thousand if you have two. Tell the dealer exactly how much you plan to put down on the vehicle of your dreams and stick to it; just make sure that you're putting something down.

3. Knowing What You Want

You will find it unbelievable what you can get talked into at the dealership. Never begin car shopping until you know exactly what you want. Before you step one little toe onto the lot of a dealership, know what you're looking for. Do you need an SUV? Then don't let the salesperson talk you into looking at a family sedan. If you need a navigation system, don't settle for a used car that doesn't have one. You don't need to know the exact make and model of the car that you want; that's the dealer's job. What you do need to know, and communicate effectively, is exactly what you need.

4. Spewing What You'll Spend

Never tell a salesperson what you are willing to pay each month. Once the number has left your lips, you'll never get it back. If you tell the salesperson that you want a $400-per-month payment, you can bet that that's what you'll leave the lot paying. If you can't keep your lips sealed, the number you spout should be $100 per month lower than what you plan on paying. When the dealer tells you he can't possibly go lower than $330 per month, you've still saved $70 each month than you had planned on spending.

5. Signing Today

No matter how badly you want a car, or how great the salesperson makes the deal sound, never drive off of the lot owning a car the first time you see it. Sure, it's nerve-wracking to walk away thinking that you just blew the best deal in the world. Think of it like this: The car will still be there tomorrow and so will the deal. In fact, the salesperson may be so worried about losing his commission that he suddenly finds the ability to offer you an even better deal.

When you're ready to buy a new car, it's easy to make mistakes. Many of these mistakes occur before you walk onto the lot. Know what you can pay per month, taking gas and insurance into account, know what you need, and keep your head about you. If you're smart about shopping, you'll make a deal that is more beneficial to you than it is to the dealership.

Amy Thomson  is a blogger for Monkey.co.uk, a leading UK insurance comparison site that will assist you in finding a great price on your new car policy.