Where are you located?
I would just leave it alone for now, no pruning, no repotting. Of course, if you're on the other side of the world and in an opposite season then it may be an ok time to repot but here, in August, is not the best time for that work. If you notice the soil having a hard time taking in water (re: water pools up or runs off) then I would take a chop stick/stick and poke holes in the soil for aeration. You also want to make sure the soil does not hold too much water creating a situation where roots rot. Take your stick and check the soil for dryness between waterings. Top soil can begin to look dry on the surface long before the deeper soil begins to dry out. If you are diligent, it will be fine until spring repotting season.
(dependent on location) I would take this action:
1. Summer/Fall '18 - Water and let grow. Keep an eye on water retention/absorption.
2. Spring '19 - repot in to bonsai soil and a bonsai pot (not entirely necessary), a nursery container would be fine too. If you are not familiar, look in to root pruning basics ahead of repotting. I would clip the long leader at the top of the tree down to 1-2 2 nodes at this time as well. It will encourage the lower branches to put out stronger growth.
3. Spring/summer '19 - water, fertilize, let grow. Take time to see how the tree grows and reacts to your work. You want strong growth in the spring which will likely taper off through the year.
4. Spring '20 - Hold off on repotting. If the tree is in good health and has produced strong growth over the past year, consider the future of the tree. By this time, you will likely have seen many other bonsai you admire and will start to envision how your tree may look in the future. Fight the urge to "style" it. What you want to do is set a course for the future, not "finish" the tree.
www.bonsai4me.com is an excellent resource for years-long progressions of different species if you need some inspiration, information or just want to see that progress is possible over time. Harry Harrington's books are excellent as well.
I'm a "noob" by forum posting standards ("shohin" to be exact...) so please don't take my advice as gospel.
What I have learned in my relatively short time with bonsai is that the key to success lies in your ability to keep a tree healthy and thriving in a pot. Wire on a dead tree is sculpture at best.