My dog needs to know who's boss?

I'm in the process of training my dog. She's about 2 years old. (i know its a little late) She only listens when i reward her with treat. If i try to tell her to come here, or to sit and shake she looks for the treat in my hand, and if its not there she's not in. I then attempted to keep it in the box until after the trick or command is obeyed. It didn't work. i THEN tried to just pet her after the command. She just doesnt want anything to do w/ it! I love her to death, and she is very loyal she never runs away, btw shes a springer spaniel, very high maintence and is ALWAYS around kids. I feel like she respects me, but almost in a mutual way. I'm so confused. If you know anything i want all details!!!!! thanks so much