Spiegel, the more stuff you make, the better you'll get!
I like the colours and the text on your sig, but I think you need to work on the composition. Your sig should have one primary point of focus, and you should try to arrange the elements of your sig to reflect that. With your current one, your eye is drawn to the two far edges, since your renders are placed so far out. When using two renders like that, you can either place them close enough together so that your eye perceives them as one object, make one primary and the other secondary, or highlight something else in your sig as primary. A good example of the third one is Psyke's current Death Note sig, where the text jumps out, and the images spread outwards from that centre focal point, and there is also some space on the edges so that it doesn't seem too crowded or unbalanced.