I've been doing it by playing both the dog ML and the Alternate run line.
Last night I picked Minny and Anaheim and ended up just over a unit. Thats usually the result I get when I do it this way - and its starting to add up quite nicely.
The first thing I look for is the home dog and the second thing I look for is either a number 5 pitcher vs one higher in the rotation, or an injured/slumping/shaky pitcher (Schilling/Lowe/Contreras), then I look for tired or slumping BPs, then I look for key players who might be out of the lineup - or players returning from injury because they usually start slow.
Nomar got me last night...
Still its been working.