Player > Feats > Improved Combat Maneuver
You are particularly skilled with a specific combat maneuver.
Base attack bonus +1.
Choose one combat maneuver (bull rush, dirty trick, disarm, grapple, reposition, sunder, or trip). You gain a +4 bonus to your attack roll to resolve that combat maneuver.
You can take Improved Combat Maneuver multiple times. The effects don’t stack. Each time you take the feat, it applies to a new combat maneuver.