the thing that should work on the most is blending, and also read many tutorials and experiment allot with photoshop ( my regular advice to everyone ) the text on all is to far away from the focal ( wich should be the render ) .. try to keep the text close to the focal cause now you have two focals.. the render and the text .. and if that doesn't work, you can always leave out the text it's not necessary . The colors you do look alright to me second one is your best, but the render is over sharpened keep it up ps. never do layer options on renders ( outglow for instance )
What the guy above said. Also keep borders more simple, because the ones there aren't that great to look at. Sometimes less is more. Same sort of thing with font. Also they need more... depth... if you know what I mean. Use the Brightness & Contrast option and also Ctrl+B might help you out =]
Do not center things...renders or text. Placing something dead in a corner is centering it in that corner and it causes focus to shift off of the sig.