someone has to say something, so i'll be harsh about it.
Work on getting that color scheme right. I know you were trying to go for the colory type of piece but it just doesn't work that way. Use adjustment layers to the best of your abilities; if you don't know what they are, I suggest you go read up on it and make it part of every piece in photoshop. Because all the images and vexels and whatnot have different colors, adjustment filters are a way of doing color correction on a still image.
e.g. either very contrasting or very similar
Second of all, vertical pieces are the most challenging(apart from LPs) in my opinion, due to the fact that it's harder to make it flow vertically than it is horizontally, just due to human eyes. a regular canvas(249x124px) is more suitable and easier to look over as your eyes naturally go left to right.
e.g. use of figures to complement eye movement
I understand that you know how to do a lot of things, but what I dont see here are two things: Flow and vibrance adjustments. As with all aspects of photoshop, you need to know how to make effects compliment others. It's really distracting that you don't follow a set color scheme and tend to go with weird colors, tbh.
e.g. low vibrance with clear cut contrast
Text just seems.... unnatural. As another part of the signature, it needs to fit right in there and match the style of the piece. I highly recommend learning some illy and just doing custom text, which can look great if used correctly.
e.g. use of clipping masks
tl;dr you need to learn the basics before you start moving on to harder shit. The foundation holds up everything, so that is what you need to perfect. Read up on tutorials; put your own twist on them. The focus is to emulate the tutorial and work the effects into your own piece to make something unique.
Potential is wasted if you rush through things and want to get to the top fast. Easy does it.