Hey man, as a first effort, I must applaud. I know mine wasn't that good. Are you using Photoshop? If so, check out http://www.good-tutorials.com
and play around and see what you can come up with. As with all guys who are new at it, work on making your cut outs of players cleaner and crisper, and don't worry about getting their whole bodies into the sig. Sometimes the best ones show the smallest portion of the player. Keep it up man, and keep posting your work!