mine is 7 months old and got very sticky fingers on anything... Dp said no and it ended up having a firm voice with a tap on her hand.. she soon got a grip of it of what it meant.. later on today she tried to pull a stack of papers off the table and i said no and said it again with a firm voice and again with a tap. she was getting upset but i felt bad she is my first baby
i believe you should start to disipline as soon as they misbehave, however your little one is not misbehaving, just exploring.
I would try just taking her away from the situation where she/he is causing havoc, it will probably take alot of times but should eventually get the message through. I dont believe a tap on the hand is necessary at that age either, it will be your tone of voice she understands when you say no. The trick is to keep your voice as low as possible when saying no.
Agree with Twiglett...
Although.... My 10 month old sometimes bites & I do say "No" for that (more like a shout if he's supposed to be breastfeeding at the time!), try to make it more in teaching than discipline mode (except for the feeding time antics, which is rather more in the vein of "do it right or you're not having any!")
I think it's okay to start saying no at 7 months, but only if you remain calm (firm is okay). Just be prepared to be saying it for a very long time before you can realistically expect your DD to:
1- comprehend it
2- obey it
(expect comprehension before obedience) In fact, expect obediance in a year or two... sometimes.