find tutorials to learn how to use photoshop completely (meaning everything), then after that find tutorials to make textures or text styles, then practice making your own. Soon you will become a pro if you work hard enough. Remember to give credit to anything you use by someone else
this is what I have to say.
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when you make your own stuff try to use different filters and mix them around. Most people will think your a "newb" if you just do random stuff at first but if you use that to learn what things mix well (what filters) and blending modes (for layers and tools) then you would probably have something going. One more thing is to learn how to use a couple other programs to add things like 3d renders to your art. just dont become a bryce whore
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sites for tutorials:
http://www.phong.com/tutorials/
Another place to check which the other guy said was
www.deviantart.com
this was probably more information then you needed (since you were just asking for tutorials) but maybe this will help.