I mean you've improved a bit on the v2 with the lightning.. and I like how the background is blurred and your Spartans are standing out.

Side Note: I don't know why but the spartan on the far left all the way at the bottom looks like has a hard-on... kind of weird o.O Add a border, and add your username text to the siggy. Just keep it simple Like i do on all my siggies place my text in a spot and make it overlay and reduce opacity sometimes.

On topic(again):
Perhaps try making a signature without a render maybe that would help you get started at first and once you've learned a couple of tricks then move on to the stock images. Anyway The background light in the middle is way too bright try reducing that.