Most people think play good players to learn good tactic
But I am telling you the opposite. Play newbies who just joined the server or just someone you know for sure you can beat. It builds up your confidence and you get more time to practice later stages of the game and to practice expanding and learning every inch of the map.
You can even try silly things like peons only after you mine all the gold and chop all of the wood if they are newbie enough.