Here's a few tricks from back when I joined the
circus military
1. Don't change your clothes. My sergeants wanted our closets to be ordered in a very particular way, every day. Any mistake and they would throw it all outside and you would have to redo it again. I quickly learned that if you lay everything perfectly then you won't have to redo anything if you just reuse your clothing from the previous days. Let's face it, you're gonna get sweaty anyway, and you're with a bunch of other guys so they won't mind because they will smell just as bad as you. Just the clothes you used once a week. When you go home to mum

2. Pack snacks everywhere. Seriously, get a bunch of energy bars and such. We had a chocolate, nut, honey, oatmeal mix (something like that) and I thought maybe 2-3 was enough. I ended up packing at least 20 when we had some field training to do.
3. Go early to bed, this can't be underestimated.
4. Get some friends and hang out with them. That's probably the best advise. You can endure 10 times more if you are with friends. If you're alone, you are way more likely to give up and the whole experience will be ruined for you.