I'm seeing that this community is sorely lacking in sig/tag-making. This thread is to help with your enthusiasm/curiousity. Feel free to post your work, ask for advice, ask questions, or start learning here.
Leaph: Your renders need to blend in better with the background. trying smudging, erasing, or bluring the outline to make it better. It's still lacking the basics of flow, depth and lighting.
Jimbobwe: Try your best to keep away from filters on the main focal image. The text should be kept best in line with the flow so it doesn't break the flow and focal. There isn't much to say since it's just a filtered image.
Lacici, try to place text with the flow of the signature. Also, I see you know how to blend the renders you used, that's a very good thing. Maybe you can work with borders, most of the time they make signatures look better.