I've learned a lot from making a hasty entrance into layout planning - I started three times and failed three times. The first thing to get into your head is 'what way you see your finished layout' then work back. I went from a maize of complicated paintwork to a simple twin track loop with sidings and a fiddle yard. This allows for long flowing trains of goods wagons, lots of storage and an illusion of distance from A to B. My shed measures 3m x1.7m and my baseboards are a sensible 350mm wide.
I have 15 points in total and am fitting point motors to 10 of them at the moment. I've learned to do a little each day, or when I have time and now I enjoy it more than ever. Be patient, think things through and listen to advice - sometimes, I didn't and it cost me.
Good luck