Blind defense with a plan
Defending blinds too wide OOP is a classic leak. Defend hands that flop well or can check-fold cleanly. Don't defend trash 'because pot odds' then call three streets.
Vs a button open, suited broadways and pairs defend more; offsuit junk defends less.
'Blind defense with a plan' (NLH tournaments, G1): Soft-calling covers near money is usually more expensive than missed bluffs.