When you wash, try to not get water in the seatpost. Just be judicious with the water. I use Simple Green and a brush, although I go after the chain with Dawn, seems to cut the grit on the chain better. When it's all dry, chain lube on the chain, dribble it around and run the bike through it's gears to get everything. A dab of oil on any hinged surfaces in the deraileurs, brakes, and shifters. Go over everything to make sure nothing is loose, check brake adjustment, and you should be good to go.
"It hurts so good..."