What are your best tried and true life hacks for the field?

I packed a hammock (from the US Cavalry magazine) instead of a shelter half. Less weight and sleeps much more comfortable. Rigged my poncho as a "roof" with 550 cord for inclement weather.

Don't let them all fool you--an air mattress with a battery-powered pump. Hands down. If you're in an area where noise discipline is a concern, don't use it. If not, you will sleep so much better than anyone else. All of your buddies will call you a POG... but that's only because they're jealous.

Sp4 Byron Skinner My field gear was minimal. Mt M-1A helmet, an M-60LMG (26.5lbs) 50 rounds in the gun and 400 res on my shoulder, an M-1911 in a odd ball holster configuration, 4 M-26A1 Fragmentation grenades in Flack Jacket pockets, a Poncho liner back at the ACAV and that was about it, oh yea a battle dressing clipped to my Flack Jacket, it came in handy more then the last time I used it. All the rest of the web gear and other stuff, including socks, any clothing etc. were left on our track or in the sorry excuse we call with affection Blackhorse Base. If I had it it and didn't need it, it was back in base camp. We traveled light and every time we dismounted we expected contact and to often our expectations were meet. Note most of the time after contact I had to change out the M-60 barrel, another guy in the squad also carried 400 rounds of 7.62 linked and stayed as clause as he dared to me. Our meals, not of choice were C-Rations, each track strapped on a half dozen or more cases. I was not unusual for a Calvary Platoon to be on its own for 5-7 day with refueling and ammo resupply being our only contact with the rest of the Troop. The first C Rats we got were dated 1951, it was 1966.

When I was leading my first ODA (SF A-team) in 10th Group, we spent a lot of time in the field in northern alpine environments. We were constantly crossing streams and getting our boots and feet wet. This is especially uncomfortable during cold weather or winter exercises. I had all my guys get flats (running shoes used for sprints) and we used these to cross streams. They pack up small and dry fast. Nowadays there are swim shoes that would work even better.

We also used them when crossing dirt roads during E&E exercises. The best example was at Fort Bragg when a battalion of the 82nd was trying to find 6 A-teams. They could see our tracks on the road, but they looked like a bunch of people out running. The 82nd found the other five A-teams, but not ours.

Take you duffle bag (if they still use them) to a Taylor and have him put a long heavy duty zipper on the side. That way you don't have to dump the whole thing to get what's on the bottom.

550 cord is a must. I make it into bracelets and stuff to keep it from getting tangled up.

Baby wipes, baby wipes, baby wipes. Need I say more?

a flee coller some may think its odd but they work I had 27 years 11b I almost always were one

Bungee cords and poncho hooch! Build it low to the ground. In a shrub/bush/tree for camouflage

Para-cord for makeshift rope, tripwire, clothes line, shelter assembly,making primitive weapons or booby trap's, perimeter noise makers. and for lashing and tying anything.' Including prisoners. Inside the cord has uses as well such as fishing line and snares.. Para-cord was my best item in the field... I still buy and craft with it today. Rifle sling's,carry all ditty bags, etc..
Para-cord has infinite uses and if it is weaved into the Slatts rescue weave it can be deployed in seconds. http://www.instructables.com/id/Slatts-Paracord-Rescue-Bracelet-no-buckle/