My tip is: start with photo manipulation. That's a great first step towards mastering Photoshop. And I don't mean like turning the eyes of a person on a pic red or duplicating the layer and change blending mode. I'm talking about spending at least a few hours, trying to accomplish something you know you will be satisfied with. Right now you seem to be limited to filters. Try to use/explore as many tools possible. Go to DeviantArt, check out the Photo manipulation gallery, get some ideas, find some stock photos, throw them into Photoshop and start working. When I made my photo manipulation "Love" long ago, I took a big step as a digital artist. I managed to turn a man into a statue, without touching the woman, using textures and stuff. Here is it: http://www.deviantart.com/view/18303862/. You don't have to comment or anything, just wanted to show you a good example of hard work. :P It would of course be better if I made it now, but I still think it's pretty good.