Junipers can pretty much be styled in any number of ways, and there is any number of ways to style this material... there is no right or wrong way, you have an open palette.
You can either take it to a pro to style it, like the experts do... or you can do the work yourself.
If you choose to do the work yourself, then I can only give you advice of how I would work this material.
First of, begin to just clean all the rubbish out of the tree. Dead branching, that cannot be used for jins, really twiggy and unhealthy branching and foilage and obviously dead material.
This process is called cleaning out the tree. And it the most important part of the whole styling process.
Why?
Because, it is where you become familiar wirh the material , you learn what is in the material, and what the material has to offer you in the way of styling.
As you go through the tree you are looking for a couple of things to lead you on the path of the materials style. These being areas of very strong growth and lots of branching, areas of very weak growth and little branching, and any unique interesting characteristics that the material has that might set it apart from any other material, such as a cool bend in the trunk, branch, etc.
As I said at the beginning, you can style junipers in very many ways, so at this point I am not concerned with how I will style the tree... just concerned about cleaning it out and learning what the material has to offer.
Why?
Well, what is the material telling me? It is telling me that certain areas of this tree are very healthy, other areas are not. That unless an unhealthy area really has something to offer in the way of a unique feature, as mentioned, that makes it worth spending twice as long to develop or more, and to try and divert energy away from a healthy side... then I am wasting my time and the tree's time in the process, and this weaker material should be eliminated.
Styling a tree, is nothing more than a process of elimination. Eliminating what is bad, and showing off what is good.
Now, before I go through and eliminate the bad, I first examine then what I can do with what I have that is good.
My goal here is to examine what I can do with the good portions to make almost a finished looking tree from the start. This way I can spend the years after just refining the tree and building up the foundation I have set up for the tree.
Consider the time factor again here... if the really good growth is on leggy branching that will take years to try and chase back, it might be better to go with "ok" growth you can grow out. Always, always, always faster to grow out then chase back and more healthier for the material. Not to mention adult foliage is easier achieved on growing out then cutting back... this process is pretty much fool proof to designing a tree.
One last thing, with material that has juvenile foilage, you need to begin to pad this out to more easily obtain adult foliage... by this I mean if you examine a main branch of foliage, you will see that there are finer branches of foliage coming off of it... often this is hid by the foliage itself, and often there will be lots of foliage coming out of the base, or notch of where this finer branch meets the main one. This needs to be eliminated, and as well about at least an inch of it does on the finer branching, so you end up with what looks like a lollipop... a stick with a puff of foliage on the end. When first learning to style bonsai be careful as to not eliminate too much and make the finer branch now to leggy.
This will allow for dryer conditions for the foliage at the end, room for wiring, and allow the foliage to quickly change to adult. Be careful for the first month if you live in a dryer region, or get a lot of sun, you do not want a region that was used to staying more moist now drying out to fast, you have to ease it into it... so hit the tree's foliage with the hose once a day.
Good luck! Of course you know, I also have numerous threads on how to do heavy bending if need be, and you can always ask!