James, Im basically self taught in my guitar (and it shows cause after 30 yrs most kids play better than I LOLOL) I just start by writing what hits me. To be honest its usually angry stuff and I write to get it out. how ever I write some fun stuff and sentamental things also.
As to how, let it flow naturally, start humming and then the chords put them selves where they need to be. Some times I can not get the chords, That is when I come here and ask one or two of teh guys for help. Ill ask for a certain sound/mood and say minor or major. If I knew Theory I would be so better off. To quote Sean Connery's character in Finding Forester "The only way to write is,, to write." so I do. even if it sucks, i have scraps of stuff that I save and sometimes I jigsaw 5 yrs of scraps together. They take me in directions I dont expect.
Hope in some way this helps.
Oh and welcome to a great site!
“Find your own sound. Dont be a second rateYngwie Malmsteen be a first rate you”
– George Lynch 2013 (Dokken, Lynchmob, KXM, Tooth & Nail etc....)