That was Wyatt around Landon's age, too!! He'd grab at the TV cords or something and then when he got a swat, he'd laugh and keep on going. We started time outs early (like around 8/9mos when he was still cruising). Even at that age, I would tell him no with warnings (3 for each 'wrong', now it's 2 warnings and soon enough we'll be down to one warning) and then he'd have to sit in the Bad Boy corner for about 40sec at that age. The first dozen times I had to keep putting him back to sitting but now he sits on his bad boy stool and pouts or cries. It's worked really well for us. It's definitely not a first time's magic type of thing but if you're consistent, it will sink in.
I still have trouble not laughing with Wyatt sometimes but once Landon starts talking back at you, it gets easier
Saying no at his age is pretty pointless. Your dh probably startles him so he knows to stop. Plus saying no over and over will make him become immune to it. I have only had that specific problem(cabinets) with my youngest and I taught her how to close them, rather than trying to keep her from them. I just say "Victoria close the door for mommy" and she does, then we go and play with something else. We've been doing it that way for over six months and now she very rarely touches them(except to close them when I leave them open ) it's annoying because it isn't effective right away but in the long run it works.
we use a time out bottle and have since the girls were about a year old Relax Bottle/Time Out Timer « My Crazy Blessed Life!
The issue you need to look out for is as he gets older you do not want to be the push over parent. Starting now to find a way to get him to listen to you is imparative other wise he will NEVER take you seriously. You just need to find the method that works for both of you.
I highly, highly recommend Positive Discipline for The First Three Years. We've been using it with Aubree (who is EXTREMELY strong-willed) and it's incredible. Game-changing. It talks about instead of teaching them what they SHOULDN'T do, teach them what they SHOULD do, and a number of other techniques and how to implement them.
Positive Discipline: The First Three Years: From Infant to Toddler--Laying the Foundation for Raising a Capable, Confident Child (Positive Discipline Library): Jane Nelsen Ed.D., Cheryl Erwin, Roslyn Ann Duffy: 9780307341594: Amazon.com: Books
Seriously an awesome book.