RE: how to draw back
Several things come to mind.
Cover is number one. I don't care if you're in a tree or on the ground, if the deer is in the wide open, its very difficult to draw back on them without being detected. Back cover helps some, but it still is usually not enough.
Secondly, try to draw on the deer while their head is behind something or, if he's got his head down and is walking, you can get away with it....sometimes. The key here is to have the bow pointed directly at them and draw slowly and smoothly while they are walking. If you're pulling too much weight, you'll sky your bow and make a lot of movement. A good way to find out if you are pulling too much is to put on every single peice of hunting clothing you'll wear, sit flat on your butt on the floor and try to pull the bow slowly and smoothly without moving the bow. If you can't, there is a good chance you are pulling too much weight.
I can shoot a 70lb bow almost all day without issue. However, for hunting, I shoot my bow turned down to 61-62lbs. I can pull it level and slowly this way.
Make sure you have fleece, moleskin, or some other peice of quieting material on that rest. You MUST be quiet when pulling back.
Watch the body language of the deer. I take it your young. You'll learn from experience. If a deer is on alert or appears nervous, it will be much more difficult to pull off a shot. In this case, wait, let them get behind a tree or other cover before drawing back. Even then, becareful. A deer on high alert is ready to bolt in a millisecond. Aiming a bit lower in the vitals is usually a good idea in this case. However, if the deer is out past 30yds and on high alert, I'd rather let that deer walk than risk a bad shot.
hope this helps