First one - Can't read the text is very hard to read and the background is not very interesting.

Second - Text doesen't suit the rest of the sig and yellow is the wrong colour for the lines and text. The render should have the black border taken off it and be blended slightly into the background.

Keep creating!

In the first one - I'm not really able to make out the main phrase... maybe fill it and give the background a bit more spice

For the second one - You should probably do something to that big, empty black space. Also, if you could brighten your render up a bit, and maybe not chop out the top part of his head, he should be looking pretty sweet!