not the greatest but that where i started out. Try following some tutorials to get some ideas. Sig 2 ftw.
First and third... Scary... Hitman one is good just some pixelated effects and ur text on all is to big and bad color and placement. i would say yes, check out the tutorial section and just follow em step by step maybe until you get knowledge of all the tools and was colors and effects work good.
im saying those sigs look like what i used to make. everybody starts somewhere. look around the forum, there is a section for tutorials - follow a few of them and learn some more techniques. and the hitman is the best, just needs some touching up