I'm really new to MLB capping (1+ year into it) so take it for what its worth.
You can approach it like Bobby mentions, stats crunching (very tedious but worthwhile).
- Looking at pitcher and recent performance (2-3 games).
- Team batting recently (last 7-10 games).
- Relief pitching performance
- Umpire preference (does he call mostly balls or strikes - impacts pitcher performance).
- etc...
Or you can look for momentum plays. Is a team on a winning or losing streak (3+ games).Public typically bets against winning streaks continuing. These play out well in the first 1-2 months of the season but don't fare as well later. I think because teams get things ironed out (bring players up or trade for players, etc...).
One play I like is to look for a team with 3+ game winning streak with a high win% (60-70+) on the season. I'm betting the streak continues typically, unless they are coming up against a great pitcher (i.e. Cole, Degrom, etc...). Then be wary. Also never pay too much juice for a team (more than -170). Its tough to makeup for if they lose.
Look for a team with a losing streaks (3+ games) that has a poor record (<35% win rate) that has their next game on the road against a winning team (50%+ win rate). Bet the home team. Typically you'll be paying juice on these but it can be profitable but again avoid the high juice.