A lot of really good advice in this thread, try the suggestions that interest you, then settle on the ones that become most comfortable for you and practice.
Addressing your specific questions, here is how I do or did it
- Shooting Angles: 35 years ago I put a ladder on the side of my garage and set several 3D targets around the backyard. For the next four months my brother, stepson, and I practiced elevated shooting for a couple hours of every weekday evening. On the weekends we went scouting in the mountains for elk and mule deer, stump shooting whenever a particular shot caught one of our eyes. Rolled rubber balls down a gravely/rocky road to practice moving targets (We were really fascinated by Uncle Barry’s running shots on deer.).
- Arrows: I started with wood, went to aluminum, then to carbon, and back to wood around 95, any critter I missed was on me, not the arrow. First, Tune your brace height to the quietest point with the least amount of hand shock. They are almost always the same. Next, find your preferred arrow and the adjust tip weights until you get good arrow flight. Now stick with your setup. AO Adcock has a great set of instructions on how to do it right, you should be able to find it by running s search. If not, send me a pm and I will send you the file. Once done, keep the same setup, make it your best friend instead of chasing the newest and greats bow or gadget.
Too many people spend their time trying for perfection rather than getting comfortable and familiar with a killing setup. I have shot 58# @ 28 1/2” selfbows with a 615-640 grain arrow since 1998.
- Fitness / Training: There is no substitute for hiking with your hunting gear or similar weight, in the same type of terrain you hunt. Scouting, along with stump shooting is a good start. For me, I feel the need to prepare for the toughest condition I foresee in the upcoming year and press myself press physically to be ready. Living in Montana, that means good enough shape to pack an elk out solo. I’m not a gym rat, so hiking the local M on the steep side starting in April with a 30# pack every other day, adding, 5-10# every few weeks. By the first part of August I have build up to a 105-115# pack, and then back off for the last 3 weeks before the season opens to 60-70#. On non hiking days I do several sets of pushups, sit ups, burpees, and balance exercises.
Shoot your bow daily, proper form will build the muscles you need. I shoot both right and left handed, you could try drawing your bow from both sides to keep balance on both side of the body. You do not have to shoot an arrow.
- Trad Tackle Maintenance, Protection and Repair in the Field: Been building my own bows for almost 30 years, I can fix/patch most anything that goes wrong. I do not bring a spare bow. My repair kit: Two spare strings (set up, shot in, and ready to use), a little bit of wax, ceramic rod and wet stone (also for my knifes), sinew, and supper glue.
Final thoughts:
It is not a matter of how many arrows one shoots, rather the quality of the arrows released.