Where to start with discipline?!

[CrapCoffee]

At the moment we're having trouble trying to get our 14mo to do ANYTHING we tell him.. in short he thinks "no" is a game and becomes hell bent on repeating whatever behaviour we were trying to stop - from getting him to stop throwing food bit by bit from his high chair to hitting..
For example He's now taken a habit of trying to attack our poor dog, I think our little boy thinks he's being gentle and is trying to copy us by "patting" the dog but he does it with so much force and then proceeds to jump/clamber on his head! Everytime we say "no" or "don't do that" he finds it hilarious and keeps trying to hit the dog, if we remove our LB from the situation he will constantly keep running back to do it over and over again.

I know we're saying "no" too often (and he quite often walks round the house saying "don't do that "Where to start with discipline?!) but I just do know where to start or how to get him to listen?

He's such a lovely little boy full of kisses and hugs but currently living up to the stereotypical "naughty" boy behaviour.. I totally understand he's too young to fully understand his behaviour but any hints/tips/advice gratefully received (before I lose my marbles Where to start with discipline?!) x

I've never actually had a 14 month old myself (youngest was 2.5 when adopted), but in the absence of you getting any other replies ...

I think you should use positive words and distraction:

So 'food stays on the plate' not 'don't throw food'
or 'we sit nicely in the buggy' not 'don't stand in the buggy'

with the dog can you take his had and continue to show him how to stroke the dog (stroking might be easier to get right than patting), and say 'this how we stroke Rex'

with things like electrics pick him up and move away with a comment like 'cables are dangerous, lets play with Panda'

and repeat.
ad infinitum.

doing the desired behaviour has to consistently be more fun and get more attention than the non-desired behaviour