Making a model car go straight

I am building a model car, it has to travel 10 metres, but I am sure the car will not go striaght.
Do I need large/small wheels? or is it the angle of wheel relative to the ground/car?
Any suggestions to help make my model car go straight?

PS- the size of the car is about the same size as a shoe.

Thanks in advance.

Are you responding to a Straight Dope column by Cecil Adams? If not, it would be better to post this question on “General Questions.” I can move it if you like.
Jill

oh sorry, i’m a new user.
Putting my quesion will be appreciated.
thank you very much.