Hello all,
Just made a snap impulse purchase at my local DIY store, a juniper. Still in it's original plastic container, it was on the reduced rack, and I fell in love with the trunk thickness and shape. Just looking for some advice. Initially I was going to create a sweeping tree, but not so sure now. It will be my 1st tree in quite a while, probably over 20 years. I purchased a Chinese Elm from a local nursery that suddenly died about 5 years ago, and I have the itch again.
I give praise to the interwebz for sites like this!!

My best recomendation is to do nothing. Now is not the right time for pruning, repotting or styling. Just grow it on for now. Meanwhile there is a lot of time to find out a long term design and a plan on how to get there.

Generally, junipers do get good cascading or semicascading trees. However, I find the first branch too high up for that style and I am not a fan of cascading second, third branch or apex. In my taste this is not a tree for cascading.

It is really hard to see the branch structure, so it is hard to tell if there are a good trunk line for informal upright. On the other hand I am not a fan of formal upright junipers. It kind of go against the nature of a juniper in my view.

If it was me, I would identify a nice trunkline in there and aim at informal upright. If the line is not there, I would never buy it in the first place.

So, against Tropfrog's advice, I went ahead and did a little pruning on my Juniper. Nothing major, just trying to get a better look at the trunkline. I also removed it from the pot, cleaned the root mass (mess, actually) added new soil that drains much better and it seems pretty happy. 

Oh gosh!

I understand that you are an eager beginner and want to do something bonsaish. By doing so you risk the life on your tree. Despite what you say this was a major pruning and in the wrong time of the year. But not only that. By beeing in a hurry you did not have time enough to research proper bonsai styling before starting. You ended up making a tree with major design flaws. Now, to make a nice tree now you will need to regrow and restyle. That will take a lot of more time than waiting for the right time for styling and spend the time researching the tree and basic design. Bonsai is a maraton, not a sprint.

Well, lets hope it survives. If it does and you stay in the hobby for a while, you will go back and look at your first photos and laugh at your first try. I know, I do today. The only difference is that I always stuck to the correct time of the year, which means I have far to many of them still living.