I too like to write...
i have a book in the wings that i have half written for my kids mainly.
my suggetion would be just write, write, write, to start with. Have several chapters on the go at once too so any random thoughts you have may be 'jotted' down in the relevant part.
when its all done then the fun begins of editing out stuff that doesnt work.
other than that, perhaps make contact with others who write and get published etc no matter the genre because i am sure they can steer you away from mistakes!
oz