The dimensions for your big one are extremely huge, if you had of mad it around 550x180 then the entire image would have showed up alot better. It's not that good. But then it's only your first, I tell it how it is so pleas do not be offended.
It lacks background, it is way too plain. If the dimensions of the sig/banner/tag were smaller, the render would have looked alot more cleaner and also the brushes would come up finer. Learn to blend a bit and make backgrounds, don't bother with text at the moment.
Focus on, backgrounds, blending, render placement, colours and contrasts and using brushes to a better extent.
Sorry if I come off as a nasty person, I did not mean to be offensive, If you don't know what's wrong with it then you'll never learn to correct them.
Good luck on your quest. Don't give up!
