Well considering you are looking at just some basic function of PS I would start out by looking up just some general PS tutorials and then get into the beginner sig tutorials on deviant art. That is the best way to learn, because DA has some of the best tuts. Then once you have started producing some work join a site like Planet Renders or FringeFX and start posting there for critique and they have super amazing resource sections that have so much stuff. Once you are okay at graphics come here and give away some sigs and then open a shop and start posting in the showcase section - heck even start posting your first signatures there. I am always in there to critique.