Backing up everything Solocam said, so I won't revisit those issues EXCEPT for 'bend at the waist'. Never drop your bow arm. You want your upper body to be rigid, pivoting on your waist like a swivel.
Along the same lines, if a deer is moving across you, i.e. you need to turn your body, do not twist. You will want to move your feet to turn your body, not twist. Twisting is like coiling a spring, your body will want to 'spring back' to it's original position when you release your shot (if you aren't familiar with "natural point of aim", I recommend you get familiar with it).
Another thing to add, if you are shooting standing up, it's often beneficial for new archers to use a stand that has a 'waist bar'. Stand up, lock your hip against the bar, and shoot. It gives you an additional point of contact with your stand, which can help you stabilize. Remember the bar is there, however, because you don't want to 'clank' your bow against it while you're standing up, drawing, turning on game, etc.
One thing I'd highly recommend, since it sounds like you already have your stand positions picked out: take mental notes of different landmarks at different ranges, even hang range flags at certain points of your hunting spots. The shorter range of bow hunting gives hunters the luxury of being able to demarcate their spots prior to season, so you can be less dependent upon rangefinding at go-time. I put flags on trees, fence posts, bushes, etc in 10yrd increments from my stand, radiating around the stand in all directions. Having that reference grid on the field gives me a few advantages: helps me avoid buck fever by adding steps to the checklist (i.e. things to focus on to stay calm, "ok, he's between the 20yrd and 30yrd flags easy shot, breathe, draw, shoot), it gives me a reference so I can quickly range my target without pulling the rangefinder, gives me a back up in case my batteries crap out, and helps me practice 'eyeballing' distances too.
One other thing that new bowhunters often mess up on is drawing a bow too heavy for them, or not practicing enough to be able to draw smoothly. If a deer comes in slowly, you can't be reliant on drawing while he's 60yrds away so he doesn't see your shaky draw, then taking a 20yrd shot. Equally, if a deer comes in hot, you need to be able to draw quickly, quietly, and smoothly so you don't spook them. You should be drawing a bow draw weight that you can draw and let down smoothly and quietly, as well as one you can hold for a minute or so to wait for the right shot.
(Keep in mind, as I'm saying this, I'm a proponent of strength training and practicing with your bow enough to be able to smoothly draw a heavier bow than you would be able to handle 'normally'. Most people, no matter how much they practice, will never be able to PROPERLY handle an 80lb bow, some people could never handle a 60lb bow. But MOST adult men can gain strength through practice to handle a 65-70lb bow. So start shooting a lot!)