Steps to painting a car

Well, Im working on painting my car, (Already bondoed and sanded) But, im not sure exactly what gives it that glossy look when painting a car.

I tried using some Auto Primer, and that didnt work out so well.

I dont want to be spending over 100$ (All I am painting is half of a door)

So, Could anyone list some supplies, the cost for them, and a place to get all of it?

THANKS IN ADVANCE.

Heres a pic of work in progress.

Painting half a door? You cant do that bro and have it look decent. And if you dont even know what clear coat is, please take it to a pro and have them spray the door. Save your money and do it right