if you're just writing it for yourself, or to print on your own, any margin you like is ok...
if you intend to submit it to agents or publishers, margins must not be less than 1' and 1.25' is pretty much the standard... plus, you'll also have to double-space the ms and should use a serifed 12 pt font... courier seems to be the most-preferred and is easiest for agents/editors to read, imo...
if you'll email me, i can send you a ms format guide and basic info on publishing... will be glad to help you with spelling and grammar, as well... hope the treatments work and you'll be well soon...
love and healing hugs, maia
maia3maia@hotmail.com