After grain crush and pH, look at your sparging technique.
Batch sparging is said to be less efficient than fly sparging, though on the homebrew scale that's not a huge deal. Also, batch sparging in two batches (each of half the total sparging volume) seems to get me better efficiency than throwing all the water in one batch sparge.
Remember that not every grain bill will get you the same efficiency. Wheat and other unhulled grains can stick together, which traps liquid and sugar, reducing overall efficiency. Rice hulls are usually the answer to this problem: a half pound in any mash with over 35% wheat.
One efficiency trick is to add a handful or two of rice hulls to every mash, even all-barley mashes.