I've seen people have like, their creation, and then lighter text in the background, and its awesome. I'd like to learn how to do that, but I have no clue what it's called. Someone help please? Do you lower the opacity, or what??

Example?
but if you want light text in the bg you can lower the opacity.

Excuse me for using my own artwork, but it's full of different kinds of semi-opaque text.
[ http://www.freewebs.com/shatteredxglass/valentine_main.jpg ]
The black text was set to overlay making parts of it trasparent, the lisght green text towards the bottom was set to soft light, duplicated, and the duplicate was set to 50% opacity. The gray text in the upper-right was just lowered from 100% opacity to 40%, and the white text going across the middle was, once again, set to overlay. The large black handwriting text was just lowered from 100% to 35%.
So, there's lots of options. I personally like soft light and overlay best for that, but screen and multiply can look good too.