Several have discussed having a niche market. Well, it has worked well for me before I even knew that there was such a thing. You see about 10 years ago we were working with a group of investors that wanted to buy property within a certain price range that was commercial. We advertised for such and were soon contacted by the owner of a marina on a lake about 125 miles from here. That was the beginning.
We went on the listing appointment and somehow managed to say the right things because we got the listing. At the time we had no idea what a block anchor, a winch system, contour line etc. were but we'd listen and then go find out. Heck, we didn't even know what due dilligence was.
Somehow we stumbled through and ended up selling the place. From there it just took on a life of it's own. We were contacted by another owner and began to work with him; this time with more knowledge behind us and then as the story goes; and he told a friend and he told a friend and on and on. Soon we DID know a lot about marinas and the TVA guidelines and became known as marina experts. From there we branched out to selling other waterfront properties and fast forward to today.
You can do it. Just find a type or aspect or area that interests you and begin pursuing it. Most people don't have the perserverence so eventually you will stand lone in your niche. Did we get rich fast? NO NO and NO, but, eventually it developed into an easy living.