if you are looking for a capper to follow, a suggest you look in mister_mj thread. he has system that produces a couple plays a week, but its hitting at a very high rate.
if you're look to cap yourself, the suggestion to play dogs is definitely a good idea, because you can hit 50% and still be profitable. avoid betting public teams like because they get an even lower lines because of the majority of the public betting on them.
you should look at team form, because baseball is a very streaky game. one team can hit lights out a couple of games in a row, and then cool off. how are the batter doing against this kind of pitcher. an average pitcher can be on fire, aswell as wel known star-pitcher cant who cant control his pitches. bullpens also play a big role now, so you need to look at that factor. how are the closers doing, the whip, era etc., but not only those stats are important, also recent performances.
many factors should be considered, but i should've made a top of advice. 1. bet small favs and dogs only. 2. recent form of a team/pitcher (play against teams that has cold bats or a shaky starter). 3. use money management as always, because this is even more important than winning bets.
good luck on your action.