First time dog owner needs advice.

I adopted a 10 month old greyhound-pit bull mix from the local shelter
on Tuesday. He's got a lot of puppy energy, and needs to redevelop
some manners since he was at the shelter for four months. I've been
doing some things that I'm not sure if they're right or not. He begs,
so I just completely ignore him when I eat. When I'm done, I put a
carrot in his treat bowl. He's not allowed to eat anything that I
haven't given to him directly, or put in his food or treat bowl. Same
with toys, he can't play with anything that I haven't given to him
directly. Is this helpful, or am I just being a meanie? The real
reason that I wrote here is about what happened today. I'd been
walking him 3 times per day and giving him a lot of outside time. I
was sick today, and it was really cold, so we didn't go outside. He's
really needy, and he won't stay outside, or anywhere for that matter,
if I'm not there. As a result, he was super hyper from lack of
exercise. I tried to put a dog sweater on him, and he put his mouth on
my hand. I stopped trying to put it on him. Later, I was petting him,
and he did the same thing, only he seemed like he was trying to play
with me like I was another dog or something. Each time he did this, I
said no and acted very disapproving. I put him in time out too, but I
don't know that he got it. Was he playing, or warning? This is
totally unexceptable to me either way. He's going to be too big of a
dog to pull a stunt like that in my opinion. Also, his old family
obviously let him on the couch. Thats fine with me, but I'm not a big
woman, and he steps on my rib cage and it really hurts. Is there a way
to teach him a code word for scoot over, or get off, or you're hurting
me? Also, a woman can do just about anything to him, but in most
encounters with men, especially unkempt, grey haired, white men, he
ends up pulling away when they pet him and growling and eventually
barking. I don't know why, but I'd like to stop that behavior as well.
We're going to go to obedience class, but it doesn't start until May
23rd, and I don't want him to develop any permnant bad habits in the
meantime. He's a really sweet dog, who loves people and other animals,
but he needs a lot of work and I don't want to mess it up. I'd
appreciate any help you could give.

TOTE...

Sounds like you are basically on the right track. I don't know what you
are doing to change his behavior to the grey haired guys. Make sure you
(a) don't correct by something the dog views as negative (b) do get him
around those kinds of people BUT stay outside his reaction zone. And make
good things happen when those people are around. Manners and obedience
must be developed but fear isn't made better if bad things happen when the
frightening thing appears. Also you want the dog to be free to express
fear, otherwise you get no warning before a bite. The structure you are
providing in other ways is fine.