Some good info in this thread. Fatigue - when you are feeling fatigued, stop. When you find you are getting "lazy" with your bow arm, and the bow seems to drop as the shot breaks, that is a sign it is time to stop.
When you start shooting, it is tempting to shoot a million arrows a day cause it's fun and free, basically. Ease into it. You will be using muscles you had no clue were there.
The bow: keep the draw weight reasonable, some "farmboy" types that throw bales around all day can draw a 90 pound bow, all day, but when drawing, if you have to point it at the sky, it's too heavy.
Modern compound bows store so much energy and are so efficient that a 50 pound bow of today does what an 80 pound bow of 20 years ago did.
The most common weight of bow sold now is a 60#. Then again, as you become part of the weapon when you draw it back, you may find yourself steadiest with more weight.
Get a set of custom strings. If they are pre-made, in a package on a shelf, they are not custom regardless what the name may say. This way, the servings will be appropriate for the wheels on that bow, and they will be pre-stretched. The string and cables are the absolute most important part of the bow. When you draw the bow, you feel like you are pulling about 60# or so, but the limbs are under about 5 times that much stress, and the string and cables are what hold it all together. I used to stretch mine, well, enough to bend a 1/2" x 3" plate of steel about 3/8 inch over 5 inches. This removes any creep from the material. I don't make strings anymore, but I can point you to the best guy around.
Longer axle to axle bows resist canting. Longer brace heights, mean the arrow is in contact with the string for less time, therefore torquing the bow will theoretically have less effect. Those two factors among a few others are what make a bow more "forgiving" to shoot, but they are not everything. One of the bows that I shot best was a Bowtech black knight 2. A Speed bow from 2002 with a really short brace.
Get good practice. Set up a target, 3D or otherwise, and once you have all your sight marks, or pins set up depending on your sight, pick a shot, estimate the yardage, make your shot, the range it whether you nailed it or not. 3D instills some horrible form and terrible habits. Think: you can be off on your range by 10 yards, and flinch when the shot goes, but still "NAIL IT"...... and a lot of guys do....
Make every shot a learning experience, whether it was a success or not.