Not a bad start man, it seems that you put more thought into your pictures than most of the new people here at GTP...it seems like most people just go crazy and take a bunch of crappy shots and post them up...but you didnt, and i congratulate you on that. You composition is good because you try to incorporate the scenery and surroundings into your pictures, this is always nice, that deep forest one would be really nice if it wasnt soo dark, it could def. use some brightness...i like what you tried to do with your second BMW pic, although the people in GT4 dont look very well made...but you cant help that...these would look much better if touched up in photoshop some, but if you dont have photoshop you could always try out some free software such as GIMP...plus there are numerous tutorials to teach you how to make your pictures beautiful....nice start, keep it up, keep putting thought into your photographs, and i believe good things will come from you!
About the banner, it depends on what you want in it, but you will need some sort of photo editing program that has a crop tool in it, so you can crop out a sort of banner shape...