Ooo nice.
You make me wanna fire up PS CS6 myself, but alas, those days are behind me.
Your banners are good, but I would say, like you've pointed out, focus on a focal point. The render tends to be it, and usually its the face, so use the rule of thirds (use google/wiki if you're unsure what it is) for focal positioning.
Beyond that, colours and borders and effects are something you get better and more comfortable at with practice which I'm sure you'll master in no time seeing as you don't seem to have any issue in that department
Scope out my old thread here:
http://zeldadungeon.net/forum/threads/viral-mazes-gfx.7543/
Hopefully it can give you some insipration.
Anyway, I'd like a sig, good sir!
Images to be used:
http://i.4cdn.org/wg/1443751115165.jpg
Preferred Color(s): Up to you, but I like the current colour/tone
Text: VRLMZ
Other information: Just do you, I don't wanna limit your creativity in any way