Don't hit. That sends the message that it's okay to use force. Plus, a young child can't yet connect his misdeed to your response.
Don't overuse the word "no". Toddlers who hear this term all the time will tune it out. Focus on what he can do instead: "Why don't you jump on the floor, not the couch?"
Don't cave in when she cries. If you do, you'll set a precedent for future sobfests.
Do stay calm. Yelling may startle or scare your child, but it won't improve his behavior.
Do catch him being good. Shower your child with kisses, hugs, and praise when he listens or behaves well.
Do make eye contact. This shows respect and commands attention.
I admit that I don't do some of them but it makes sense to do them. So, if you are a parent who is having hard time disciplining your toddler, learn from the expert.