[The Trigger]

I'd prune back the longer branches in each of the top corners and the longer one on the left side of the tree. I've done this with mine and it should make for a more compact and bushier tree. It's also a younger tree so you could always just leave it alone and see where goes

 

[The Trigger]

I know most trees are gonna send most of their energy to the top of the tree and try to grow taller. If you want to fill in that forked area I'd say prune heavier on the top of the tree to allow some of that energy to be used up by the bottom and middle branches. It's hard to really tell how it's going to look because it's so young, but you can train some of the branches to go where you want them to. Same concept as a bonsai tree. It's a great looking tree, it looks very healthy so I don't think you're going to have any problems trying to get some of those areas to fill in, just may take the rest of the season.