Teach and Train.

Aren’t you glad that you are not given a job to do (without any training) expected to do it right from the start? It makes me think of the old I LOVE LUCY show when she and Ethel are on the candy making conveyer line. They didn’t get much practice before they were expected to do the job of covering candy in chocolate quickly and efficiently. They wound up with candy everywhere!
When I am at work and I am being trained to do a new task usually someone is working with me to show me how to do it and answer any questions. At some point I branch out and try it on my own but have someone there to remind me how to use the new program or create a new invoice. I sure am glad that I am not just expected to KNOW it or get fired!
Very often we tell a child to do (or NOT to do) something and then discipline if they don’t respond correctly. I would encourage you to teach and train your children BEFORE going for the discipline. Discipline AFTER your child has mastered something you have taught him but chooses to disobey. Take standing on the coffee table as an example; first, make sure you are setting a good example, don’t stand on the coffee table (lol) . Second, teach your 18 month old not to stand on the coffee table by removing him and telling him “we do not stand on the coffee table” while setting his feet on the floor—repeatedly. Yes, over and over and over again. It is not a FUN thing to do but sometimes teaching is required but not enjoyable. When you see him look at the table and choose NOT to climb on it, tell him how great it is that he is NOT climbing on the table. At this point you know he is beginning to understand that he should not climb on the table. AFTER this point if he chooses to climb on the coffee table you can reinforce what you have taught with age appropriate discipline, perhaps by scolding when you remove him- giving the instruction “we do not stand on the table” a little more sternly and setting him on a stool or small chair for a few seconds. You may have to work at teaching and training for a little while each day for a few days but he will get the idea. The point is not to expect your young child (at most any age) to hear an instruction ONE time and immediately know how to act accordingly.
Be the PARENT and get the results! Stick with it! Teach and train before you discipline.