1. I don't mark bad sits/ behaviors, I ignore and try to repeat the scenerio for what I want.
2. You can do what you want, but I find if a dog doesn't know what your asking him to do, throwing a bunch of different things in the mix, makes it more confusing..My dogs become 'bored' when they "know" something, and I do NOT move on..I keep my sessions short, to the point, and do a few each day..working on the same command if I have to.If you think the dog is becoming bored, stop, give it a break and go back to it later. Teaching obedience CAN be boring, it's getting the dog to "want" to do it, and what that reward is at the end that will motivate them "to" do it.
4. Use the "wall"..have him stand next to it. YOU get in the position YOU want the dog in, and work it. You can use 'heel', place' whatever..The dogs right shoulder should be next to your left leg. that is a heel position..
All the gsd's I've had have not been 'cream puffs',,if said "masi come on over here', is a sweet sappy voice, she'd blow me off, when I give a command, I usually have to do with an authoratative voice and a voice that tells that dog, I MEAN WHAT I AM SAYING. I'm not saying my dogs were stubborn, they just need me to say it like I mean it..so voice inflection/tone, has alot to do with whether they are taking me seriously or like "HA, yeah whatever" ...
I have taught a walking down/stay, by first knowing the dog knows what down/stay is, walk, down/stay, then I throw something else into it, walk/down/stay, I TAKE A STEP,
I back up, release the dog and walk..work on that, then the next time (which maybe a couple days, I want it solid!), I'll take two steps, pause, back up continue..etc..I then get to the point, where I walk/down/stay, and "I" continue to walk, in a big circle, go back into that heel position, stop, release the dog (lets' go), walk with the dog..
Masi has been a pretty good obedience dog, of course I took classes with her, with a person who uses the koehler method, which many don't like, but purely / positive didn't do a thing for us, food was not amotivator for her, praise is..she loved those classes, go figure