Some kind of tough glove or open-finger glove - the rough rocks and sharp edges will hack your fingers and palms when you inevitably stumble.
Gaiters - when you scree ski, no stones will enter your boots; also protects your shins while bushwhacking (because Kane's trail directions on obscure outings often leave guys like me with scarred shins).
Rainshell or light repellent plastic jacket - 'tis a very miserable situation to be saturated many miles from your car (learned the hard way).
Apples - you know that exhausted feeling plodding uphill? Stop and eat an apple. In ten minutes you'll be soaring up the mountain again; amazing fruit, that.
Heavier jacket or light parka - Even on the warmest days, tie a warm jacket around your waist before you head up. The conditions can change rapidly, and the higher elevations are chilly more often than not.
More water - can't stress it enough.
