Getting familiar is never a mistake, but don't expect to do more than visit neighborhoods, research what is nearby and how traffic is between home and work and home and shopping and so on.
You should start soon to check out your credit score and repair those problems, if any, now. Some things might take months to resolve, and the final 12 months of your credit picture must be free of any late payments (or collections).
In February or March, you should begin looking because the closing process will take about 5 or 6 weeks. The market usually heats up significantly in April. If you don't mind competing with others, you can hold off until 2 months before you want to move.
On the other hand, if you thinking of building from the ground up, December is when you need to get started.