Nice sig for your third bro. In your next sig, try to:
1. Blend the render with the background, but do not just smudge the outside of the render.
2. Try to build some depth between the focus point (the render) and the background. Remember that the things closer to the viewer's eye seem sharper than the objects in the distance. Thus, experiment with the sharpening and blending tools.
3. Lightning sources. Light is always an important factor to consider while creating art. There is always a light source, right? Outside there is the sun, inside, the light bulbs, and so on. Try adding light sources, but do not make them sharp, rather blend them in.
I like that you put the text diagonally, as things always look better in creative position, rather than the plainly horizontal placed ones. Try to experiment with blending the text into the background.
This is all the advice I should give you for now, as it is already a lot to work on at your level. Keep up the good work!