Sometimes letting the water sit in the fridge for half an hour helps, especially if it tastes of chemicals. And don't ask me why, but pouring it from one glass to another a couple of times can improve the taste.
I found ice works best. The colder water is, the more enjoyable it seems to be. A filtered pitcher also helps, not just because of the purification, but because it stays in the fridge and keeps the water colder.