Most babies/toddlers are walking pretty well by now, with fewer wobbles and stumbles, but you should still keep an eye on him as much as you can. He'll like to push and pull toys as he's going, and will be competent enough to be able to bend or squat down to pick things up, and will be trying to go up the stairs any opportunity he gets.
Discipline is getting more important now, and there are two main methods of it - using power and using reasoning. Power involves taking away certain privileges, using corporal punishment, taking affection away, etcetera. Reasoning involves making children understand what they did and why it was wrong, and over time children will be more eager to cooperate this way.