This is a nice maple. Clearly someone with a set of skills has grown this. Your work? Or did you buy this from someone?
If the latter, I would recommend finding someone close by to work with you in developing this tree further.
The first question in my mind is.. What do you like about this tree. If you recently got it, why did you buy it. I could make recommendations on how to further develop it, but it is your tree and you will need to look at it!
Overall image is pleasing. A nice set of branches none of them overly heavy no clear straight sections and a good nebari and firm trunk. Great!
I notice one thing which I am not a fan off, which is the very long topsection of the trunk. You have gently moving trunk, and just below the halfwaypoint the trunk bends to the right and stays straight. In leaf, you see this section also creating a crown outside the overall tree-profile. I might want to fix that BUT this will create a big cut which may take a long time to close. On pictures some of these things look worse than in person: Someone needs to see this tree in 3D to really get a feel for it.
Considering the trunk is slender, having shorter elegant branches as you have now fit well. You might have to sort through them. I think I see many branches coming off the trunk in the same place. This causes the knuckles you have on the trunk, local swellings.
If you decide to keep the tree in its overall shape as it is now, focus on branch lines. Branches have taper and slit up in smaller branches going away from the trunk. In the best bonsai you see that all the branches take up their own place in the canopy, and grow in a similar angle from the main trunk until you reach the apex. That creates a calm image. When trimming, always look for the lightest branches with short internodes. Remove coarse growth with few nodes on them. Make sure you have concave cuts, and take a sharp knife to make the edges of the cuts smooth and cover with cut-paste.
I might take a few smaller branches out but find it tricky to advice, as you would need to see the tree in 3D to really judge what is going on.
Nice tree.