Teams have differing levels of home field advantage.
The best way to see is to look at past 2-3 years and compare their home win pct. to overall win pct., something I myself have been meaning to do this spring and haven't done yet.
I'll post in here when I get it done, likely next week sometime....Or you can do it if you've got time.
Traditionally, coastal teams likely have a bit of home field edge versus teams from other coasts, due to travel time and possible jet lag in first couple days.
Additionally, historic parks/teams like the NYY, Boston, Baltimore can be modest help versus younger teams.
Places like Miami, Texas, Houston or Zona with the dome open can be an edge in July-August heat.
We give about 25cents right off the top in most cases (two even teams at -130/+120) then make other adjustments based on ideas above.