There really isnt anything we have found that stop them from doing these things. We give time out, or I come up with silly punishments like stand with your nose on the door- 1 hand on your head and 1 on your knee, then make them go give a kiss, cuddle and say sorry to the other child.
Once noise level gets too high in our house I break the kids up and give them separate tasks to do in separate places- even you draw me a flower over here and you work out how many fingers you have over here
I feel for you with 2 young 1s and baby due soon. persistence is key, just cause it doesnt work today doesnt mean it wont work tomorrow, and they will learn, sometime