Oh yeah. I have a couple of tips.
- Eat a lot
Yeah, this is not a lifting tip, but it’s something you absolutely need to do. During my first two weeks in the military I got known as the guy who out-eats the rest of the company. I’m pretty sure I was getting down over 6K calories per day. I still lost a lot of weight during the initial two weeks (and after that as well, I once lost six kilos in one week when we were on a training camp). So eat as much as you can without having it affect your performance. (It’s pretty uncomfortable to do combat practice when you’re stuffed as hell)
- Focus on big movements
This is a no-brainer. You’ll be doing a lot of work outside lifting so you probably won’t have too much energy to spare. Bench, overhead press, chins, deads, squats and the variations of these lifts should make up the bulk of your training.
- Your training should not be equipment-, lifting gear- or spotter-dependant
This ties in with the point above. Don’t pick lifts that you need fancy equipment for. Nearly every gym has squat stands, but not all have power racks - pick paused squats over pin squats. Sometimes you’ll be the only one in the gym - make sure you are strong enough not to need hand offs. Don’t depend on your belt, you may not have the time to find it or you may not have it with you at all when you’re given a chance to train. Same goes with all kinds of wraps and straps. Remember the three phased program I did in the military? It was designed so that I could train alone with minimal equipment, regardless of the schedule.
- Make sure your sessions are not too long
Sometimes you only have 30-45 minutes to train. That is enough if you’ve planned well. Again, the three phased program was great for this; quite a lot of submaximal sets with low rest followed by one all-out set (in the first phase at least) and you could even superset your movements if you were in a hurry. So either do just a couple of hard sets per exercise or use clusters/muscle rounds/myo reps to cut the training time. Also limit your exercises per session to 2-3 (4 tops)
- Do the stuff you need to do in the military
Push ups, chins, sprints, sit ups. Do them. You’ll do a lot of volume for these movements in your basic training so in the gym I’d focus on getting stronger in the 4-8 or so rep range. (If you can’t load push ups by yourself consider dips)
- There is no such thing as being “too tired to train”
You never know when the next chance to train comes, and wether you’ll be tired then. If you have the time to train, take it!
- Cut the fluff regarding warm-ups
Learn to train without a general warm-up, stretching and foam rolling. Warm up with the movements and get going. (Now to magnify the shut storm; general warm ups, foam rolling and stretching don’t have to be done if you warm up sufficiently with the movements. None of those things have been shown to help with performance or reduce the risk of injury)
- Train with a full body or upper/lower split
For the first half of my time in the military I was basically doing full body every time I was in the gym. It’s the safest option as you never know when you’ll be training again. After the halfway point our schedule became a bit more solid and I was able to switch to a upper/lower split.
- Get your work capacity up before you go into the military
This will help with performance both in and out of the gym, as you’ll be less fatigued both from basic training and lifting.
Those are the first couple of things that came to my mind, @Irishman92 probably has a couple more things to say regarding this.