When you have 2 cards remaining in your hand select the Uno button before laying one of your cards, or else you will be dealt 4 more.
Simlarly, if you had three 8 cards in your hand it would make sense to lay one of those. For example, if you had 4 red cards and 1 blue card and the current showing card atop the waste pile allowed you to lay from either color you would choose to lay a red card. It makes sense to try to keep a variety of play options in your hand until you have few cards remaining.
