First step is to learn how to spell "psychology".
Second step - go look up a guy by the name of John Watson, known as the "father of Behaviorism". Once he got sick of being a psych professor, he went into advertising, and started applying it there. This was in the 20s.
to him, it's all about associative learning, and pairing feelings together even when they have nothing to do with each other.
You see a hot babe and it gets you aroused. Now you are looking at a car - and you're aroused.
Guess what - next time you see that car, you feel strangely aroused...
ever heard of "little Albert"? that's what it all comes down to.