Well when you can afford it (like $11 US), look for a book by Owen E. Dell called "How To Start A Home Based Landscape Business". Get the third edition, it's the newest one.
Newbie: Email me (firstname.lastname@example.org) your address and I will mail my copy of "how to start.." You can have it..I did not care for it but I knew a lot of the stuff in there. Would prolly be good for you ..
I do strongly suggest the business plan.. I am a hypocrit becase mine is not done but I can either book jobs and learn the ropes or work on the plan.. I chose learning the ropes, but i am working at it piece by piece. It is a great idea. You start learning alot of stuff..