Starting an eCommerce business, or any business for that matter, can be a difficult task. Focus is critical! If we try to do everything at once, we can only expect mediocrity in pretty much everything.
Keep things narrow at first. Focus on the smallest possible problem you can solve that will potentially be useful. One of the biggest problems many new companies make is trying to do too many things at once. This makes life really difficult and can impede our progress. Focusing on a small niche has so many advantages: with much less work you can be the best at what you do. Small things almost always turn out to be much bigger when you zoom in.
The concept of focus is really logical; however, most of us seem to have a resistance to focus. Just remember, when you get to be #1 in your particular niche market and then find that niche to be too small, you can always broaden your focus.