It's not bad, I just see some quality and smudge issues.

What I believe the problem here, mainly is the smudge. You have a very bright yellow effect coming off of the soccer ball and him which is cool but in my opinion the smudged background is bringing it down because it's very boring, which again could be fixed by adjustments.

I would advise you drop the blur tool as of now because I think you need to focus more on your smudge.

Along with the smudge is the composition. I believe you're adding too many things into one area and therefore making it messy.

The quality issue I stated before is how low quality the focal is. I think the original render is a sketchy type of render which is cool but not a great choice if you're going for a smudge like so.

I would advise you map out what you're going to do and then pick the render/stock, that way you have a general idea of what you're going for.
Other artwork = inspiration and ideas and then apply your own to it.

You're definitely improving though, keep working at it !