Very nice premades, my advice would be to keep working on them. Try to experiment wtih different filters, and text effects and styles, also choose colors that compliment each other. Another thing, no matter how cool it looks, unless the render is high quality your signature is going to look bad if you use that style of work. there are some exceptions but this isnt one
just keep going and experiment with whatever you're using be it gimp or ps. Good luck and im looking forward to seeing your future work.