Great advice from Nicola and I love Karma's analogies.
When Mollie came to us at 11 months she did everything you've mentioned and more, including trying to bite us. I'd never heard of COL at the time and had to work things out for myself, having had no experience with a bolshie dog with issues. Grabbing Mollie when she'd been thieving was, as I soon found out, dangerous. At the time I thought you had to dominate the dog and the one time I tried it both Mollie and I were terrified. Being a non-confrontational person, I soon learned that if (a) Mollie didn't like being cornered - I just never cornered her and (b) if she had something of mine (which was a zillion times a day) I could get it from her by giving her a treat. At first I thought this was bribery and corruption and just not on, but then realised it worked - which was good enough for me. I negotiate by making her want what I have or can do for her, and remember that for her there's no past and no future - life is lived in the moment.