If you've knit a sweater before, then you understand the shaping, etc.
Are you thinking of making a FI sweater in the round, with steeks and such?
One book that has I think the easiest patterns is the Fair Isle Sweaters Simplified by the people who make Philosopher's Wool. It uses heavier wool than the other books, and the sleeves are knit separately.
You could also check these for inspiration.
If you have a child you could knit for, starting with a kid's sweater is a good idea since it will give you experience without a huge committment of time and money--and will teach you a lot.