Not feeling the effect on his left side. Also the effect where it looks like it's using some power its behind his hand rather than in front of his hand . I'd try to making smudge those areas in a bit to blend.
same as santa, the blue and white force cloud should be coming from his hand Might even do that by just copying that part and putting it on X% opacity :/ Would be looking better if you smudged it away from the hand though
Text is taking away from the signature. With those try and get a simple font alot smaller around the render but not where it sticks out to much. The colors are poorly done and it seems that you also colored the render like that which was a poor choice and makes the render look overall like it's LQ.
if your going to comment do so in a manner specified by the forum rules. I don't care that you hate the text because I would tend to agree I would rather much and the mods would also that you do so in a civil and non-vulgar manner
you have the idea, but it needs pretty much what everyone stated above. keeping working at it and im sure you will make it look flawless.