With reference to the future, you CAN get in shape in advance of future hunts, IF YOU WANT TO. You may have to lose a lot of weight. You may have to quit smoking. You will have to work out hard. But it can be done. Enough of that.
You will learn a lot just by going out there. I assume no one in your group has hunted elk before. If they HAVE hunted elk before, successfully, pick their brains and follow their direction. Some things you just can't think through merely by reading a book or sitting at home, you have to be there.
One of the things that is needed -- I'm speaking for future trips -- is a good camp. My first year I tried to camp at 11,500' in a backpacking tent. Not a good solution. You want some place you can get warm. This means either a tent you can stand up in with a heater, a camper with a heater, or a trailer with a heater. You need a place to recharge your batteries, to sit in a chair, in the warmth.
It is often said that he who walks the furthest sees the most elk. That is not necessarily the case, but there is some truth in it. Getting a mile or more away from the road is helpful. This tends to reduce the number of people you are competing with and the elk will be less spooky with fewer people chasing them. Be where you want to be by 45 minutes before sun-up if not earlier. A lot of people recommend getting up on a high place with a good pair of binoculars and looking for elk painstakingly with the binoculars. You need to do this deliberately and slowly. Check for elk close first, but then concentrate and further away distances. Elk are usually banded together, say in herds of 20-50. Elk, when in traditional patterns, move from bedding areas to feeding areas at first light and then back to bedding areas by about 2 hours after sun-up. It may even be the case that the elk are already in the feeding areas at first light and heading towards bedding areas. It is the reverse of this at night. I'm talking about after the rutting season is over. Feeding areas are open grassy areas, usually pretty large open grassy areas (needs to be enough to feed the whole crowd of 20-50 elk).
The elk like to be very close to treeline before the snow has accumulated and driven them lower.
Shoot and keep shooting until the elk is on the ground. Shoot at the same elk. If you shoot and are sure you missed, that may alter this advice.
Think about cutting the elk up and getting it out before you shoot. Don't shoot them in 25 inches of water or in deep mud. I have heard some people say take plenty of rope. I don't know why they said that. I usually have a fair amount of rope in camp. Maybe I'll have an experience some day that teaches me why that person gave that advice. Take two knives with you while hunting. Sometimes knife blades break while working on elk. Your blade may get dull while working on the elk also.
Drink plenty of water. Have sunglasses. If there is snow on the ground, you will want to wear sunglasses. Remember at high altitude there is more sunlight blazing off the snow and into your eyeballs. You may wish to use sunscreen on your face. We have it at my camp, but I don't remember right now if I actually apply it or not. I haven't gotten sunburned before. Maybe this is because I tend to like to tuck myself into shadows while hunting which makes it harder for game animals to see me.
When you see other hunters while out elk hunting, talk with them and politely ask for any pointers they may have to offer or even any good place to hunt. Most often people don't want to divulge their best places, but sometimes they can give helpful pointers.