http://www.babycenter.com/ which details age appropriate behaviors at different ages.
2. Can I get rid of the problem?
Sometimes we create our own problems. It took me 2 weeks to realize that moving a particular chair from the living room to the basement could easily eliminate a big problem when my daughter kept standing on it. I was constantly asking her to sit correctly in the chair and once the chair was removed....there were no more conversations about the subject!
3. Is my child tuning me out? Do you find yourself saying no a lot or correcting your children so often that it feels like that's all you are saying? Often, our children will begin to tune us out because they are overwhelmed. In fact, it's human nature to demonstrate negative behavior when all you are receiving is negative attention. Instead, provide an atmosphere where your child is forced to earn compliments or acceptance so that they feel like they can earn positive reinforcement.
Positive attention doesn't mean constantly telling your child how great they are or how proud you are of them (actually that can be harmful when overdone!) Instead, get engaged in their world and involved in conversations about what interests them "wow! That train is fast! Do you like slow trains or fast trains?"
Usually, getting down on the floor and involved in THEIR world is the easiest way start having them earn positive attention and allow them to learn they are appreciated.
4. Am I a pushover?
We teach our children how to treat us. If we give in to particular situations, our children will begin to think that what they are doing is acceptable (because it is being accepted, right?) Think about what things are very important to you and draw healthy boundaries and/or consequences around those situations (i.e. If your child talks disrespectfully to you and you never give consequences, they will continue to behave that way!) Remember, children respond MUCH more effectively to warnings and consequences (time outs or things being taken away) than they do to verbal reprimands alone!