The colors are really neat on the first one! I like the sea greens and blues with the yellow. I think some of the lines going in to his hair would be fine but I'd suggest taking the eraser and trying to keep the graphics from off of your render's face. It covers up his sexiness and you know how rabid fangirls hate filtering sexiness. You don't wanna piss the fangirls off now, do you?

I like your choice of border on the second one. n_n Unique borders can add so much to a banner! I can't say I'm too hip on the font choice. Maybe if the quote was a little smaller and not right dab in the middle of the right side.

Oh! And other people do it different but something to think about when you play with typography - you should think of contrast as your friend. In your second sig I like that you bolded his name because it does contrast with the normal thickness of the quote but its so simliar that its barely noticeable. Next time you do a quote try using something easily readable for a group of words and have fun with the person's name! Use cursive or something outlandish to spark the eye's interest. I don't know if that makes sense or not but it was something I just learned in my studies.

These are great warm ups! Please share more with us! ( Hope you didn't mind my rambling. )