Text, try make it smaller and blend in more
Blurryness, makes it look lq
Lighting, try adding a light source by using a soft white brush
Blending, try erasing or smudging the sides of the render so it stands out less
Bg, try and make the colours suit the render
The vector, doesnt flow and blend in with the sig and looks out of place
Nt though, try all those things that i suggested
Try to choose HQ renders not LQ.
When blending a render, blend it in the corners not all over it.
Make the text smaller, i want to see the sig not the text.
Use normal size, like 450x150,400x150 or smth
Make BG same color as the render, so the render will blend it more
Also, try to make a flow.
Add some effects so the sig will look more cool.