Fantasy Baseball

For the first time ever, I've accepted an invite to join a fantasy baseball league. This particular league is on ESPN. I'm pretty sure I've got a good grasp on how the league works, but I'm unsure as to whom I should be drafting.

Does anyone have a method for drafting players? I mean, I know I should be drafting the best available position player left, but it seems like there should be a science to it. Any advice would be greatly appreciated.