Most photographers start their photography-based company shooting everything and anything they like to shoot. While admirable, they risk the chance to fall into the basic trap of starting off in an over-saturated market, which is almost guaranteed to fail unless they can unseat the established professionals already entrenched in the local market.
Instead, I recommend finding your niche: that specialty where no one else (or hardly anyone else) is, where you can excel and carve out your own market.
Picking your niche.
For example, if you enjoy taking portraits of children, look to see who in the local market is offering child portraiture, and what they're offering. If most everyone is offering in-studio photo shoots, offer on-site or outdoors portraiture. If the market seems to have mostly indoor portraits, perhaps environmental portraits could be your niche.
Now, a quick warning about going where other people haven't: there may be a reason you haven't seen. Offering outdoor portraiture in Minnesota means you're going to be doing most of your shooting between May through September due to the cold weather.
Another thing is that these other niches may require special equipment (often read as expensive special equipment) or perhaps special abilities. Safety is also paramount; shooting at a client's home may create personal safety issues that should make you think about bringing an assistant who, if nothing else, is able to watch out for you.
If you like to shoot landscapes, perhaps specializing in a theme (autumn colors, urban/rural juxtaposition, etc.) could be your niche.
Find your niche, but don't pigeon-hole yourself there immediately. For example, I started out shooting field sports (soccer, baseball, football), but have since changed my niche to gymnastics and cheer-leading for several reasons (which I will expound upon in a later article). Do I still shoot soccer? Yes, as it's still lucrative enough for me to pursue, but I concentrate on getting gymnastics and cheer meets more often.
Niche photographer yet generalist.
Should you just shoot within your niche? Heck no! As I stated above, niches can translate from one to another. Perhaps you start shooting outdoor child portraiture, but get an opportunity to shoot head shots for a law firm in your town. Provided you have the ability and equipment necessary to pull it off--and more especially the desire--I'd advise considering the chance to expand. After all, if this firm is asking you, the outdoor child portrait photographer, to provide commercial-usage photography, perhaps there is an opening in your local market for a photographer in this niche.
So, choose a niche, but don't be too attached to it. Things have a tendency to change when you're least expecting it.