My first recommendation would be to listen to bonsaichile.
Once you have a few more trees, and when you know how to care for them, you're going to screw a few up. Then some more while you get the hang of it, and then a few more just for the sake of it.
In this pot, this tree isn't going out of control within 5 years. So you have all the time to take it slow.
At the end of summer, some needles will have turned brown because of their age. Get a tweezers and pull those off. That'll be your first styling.
In winter, when the bark of junipers contracts, you can think about structural wiring. I might sound like an echo-chamber, but I've learned that especially beginners can learn a great deal by not cutting anything and just doing the wiring. I screwed over 5 or 6 junipers before I found that out. And for some reason after wiring, the design kind of makes itself. It's then just a matter of reducing the amount of branches, or just keeping it that way.
If you go too fast, there's a fat chance you might have to wait another 2-5 years before you get a second try. Now if you do a hundred small things to a hundred trees, you'll be accumulating knowledge and experience fast, and it keeps your mind off of doing radical things that might not work out ;-)