Phase 10 is a bit like Uno, in that you are always trying to get rid of all the cards in your hand and be the first to do it for all hands. But unlike Uno, getting rid of your cards is not your main goal; the goal is to construct and complete your Phases (also called melds), from Phase 1 all the way to Phase 10. Discarding all your cards in hand for each round is the secondary objective (but important as well, as we shall see).
The game can be quite challenging to win, especially since you need to constantly slow down your opponents, e.g. those who have already advanced up the Phases ahead of you, and you always find yourself trying to guess which cards the person after you needs – and not provide him/her these cards (by discarding them) if you can help it. A fair amount of luck is involved; if you’ve been dealt a favorable hand of cards, it ensures a speedy Phase completion.