M.R.
Think about her developmental stage. For toddlers, you should try to tell them what to do instead of what to stop doing. It is much harder than it sounds. Instead of "stop climbing on that" say "put your feet on the floor" instead of "No hit" say "put your hands in your pockets- or arms down" Think about how many steps it is when you say "don't" anything. They have to think of the action, stop it, reverse it or find a new one and judedge correctly what is acceptable to you, and then carry that out...at 18 months? No way! Tell her what you want her to do, and she will be more successful, sucess breeds success, and when she is doing better in general, the better she will be in other areas too.
Choose a disciplinary technique, then do it every single time she miss behaves, and don't skip a single beat. If it is time out in her room or the play pen, you do it at the drop of a hat and she will get the idea in a matter of days. Stop talking ot her about it, just do it, do it often, and do it every single time. If you are in public, leave, even if it is someplace you want to be. Soon, you will be able to take her everywhere without worry. Your actions are the only langague she is listening to here.
M.