Well for a 1st it isnt bad, but it looks like you used a stock for bg and then pasted two renders on the sides :/
1st - Next time use only one render, signatures with more than a render normally arent good

2nd - The Izuna render was wrongly resized, be carefull with that

3rd - There is no color balance, in that sig you have lots of colors, orange, gey, black, blue, white, you need to focus on one or two colors so it can all go well togueter

4th - It looks low quality, always try to find HQ renders and keep your sigs clean

5th - The blending, those two renders seem like they dont belong there, you need to try to make them look like they are a part of the sig
Well this is all the CnC i can give you

Keep trying, watch some tutorials, youl see you will get better fast