Okay, so here's the deal...

Natural bogs are caused by a paradox of sorts in areas where there is both good drainage and constant moisture. This washes away excessive nutrients leaving a very clean environment. Looking at a natural bog, you might just see a wet area covered with sphagnum, but beneath that there is always a very slow constant water flow. In fact, in a trip recently to cape cod, I saw a bog between the dunes with sundews growing in pure sand.

There are lots of different kinds of bogs, ranging from seeps to kettle bogs. So the first thing to do is examine your site and determine what kind of bog you wish to emulate. I see you are in NJ, so you may want to visit the pine barrens to look at CPs in the wild. That will give you some great inspiration.

Okay, secondly you need to think about your water source. For water to work in a bog garden cannot have much disolved salts or minerals, and cannot be alkaline (in which case it would be a Fen instead). A conductivity test should tell you where your water is naturally. If you're only limitation is nitrogen, then you can seep the water through biological treatment areas first with high nitrogen using species like cattails. Otherwise, you might consider collecting rainwater off your roof in a rain barrel then slowly seep it out into your bog garden. This also has the benefit of naturally treating runoff from your property.

My bog gardens are modeled after a mountain bog, imitating natural seeps/springs where streams begin. I design them on a gentle slope to provide drainage with a curved basin wider at one end, and the other end open pointing down the hill. You can model a bog after any kind of natural system though. Go see some different types in the wild, and give some thought to how they work. After all, Nature is by far the best landscaper and should be your #1 reference for how to do things right. Through observation you may even decide to do a kind of bog no one has done before.

Hope this is helpful.