In my experience of talking with other people who wanted to become freelance photographers, the three most commonly encountered pitfalls are
1) Sales acquisition is hard because of the volume of competition,
2) customers not understanding that they're not paying for "just a photograph",
3) not charging enough to make a living beyond working an hour to get paid an hour.
A good way to lessen these is to find a gap in your local market and go "niche". That doesn't mean small, it means focussed. Figure out a few possible gaps, and start working to become *the* person who dominates that market. Everything else should fall into place behind - but it might take time.