Well for a points league I normally try to find the "chink in the armor" of the scoring system and base my rankings on that. Whereas in Roto you have to draft a balanced team so that you are competitive in every category. That's the biggest difference between the two IMO.
As far as a definitive strategy it depends a lot on how the categories are laid out. In 5x5 I normally draft one SP stud early (not 1st round) that I can start always, then the #2/#3 SP in the early middle rounds, guys I can almost always start. Then I round out the staff with 3-4 more guys in the middle to late-middle rounds, spot starters.
I load up mostly on batters early based on position scarcity except for C where I feel you can always grab good value late in the draft. I let RPs be dictated by the start of the Closer run. This is how I approach a pre-season draft. I have never drafted mid-season and imagine it's an entirely different beast.
Maine has a good swing for a pitcher but on anything that moves, he has no chance. And if it's a fastball, it has to be up in the zone. Basically, the pitcher has to hit his bat. - Mike Pelfrey