The boat likes to head one way rather than the other? Mast straight up? Rudder rake adjustments? One rudder not actually locking down? Centerboards both all the way down?

A few thoughts (other than hardware issues):

Conditions can look different from one tack to the next. You don't always get the same sea conditions and what appears to be close hauled on one tack may not look the same on the opposite tack (Angle to the waves etc).

Really be aware of the actual wind angles, use a bridle vane. Don't rely on the wave angles to determine your angle to the wind.

Different wave angles can stall the boat entering into tack. You may need more speed on that tack.

I would start the tack from further forward on the boat and get to the aft corner as the boat is closer to head-to-wind. If you start at the rear it may be stalling before you start the tack.

Be sure to crack the mainsheet as the boat gets head to wind. Otherwise it may loose momentum through the tack.