Sleeping: Sleep soundly by investing in a decent sleeping bag. We use this British made PHD Minim Ultra down bag that weighs no more than a can of coke, and is just as tiny! A decent rollmat will stop you leaching heat into the ground. This Thermarest NeoAir is thick and cushy, but packs down small!
Navigation: Forget you're fancy GPS, a proper compass doesn't need batteries or signal. We keep ours close to hand by attaching using a Miscellaneous Adventures toggle to secure it to the outside of our pack. Make sure you've packed the map!
Tools: We never head into the wild without a knife by our site. They are the original multitool! This is a traditional Puukko - a Finnish design with a fixed blade - but pocket knives will do the job too!
Clothes: For overnight adventures, we don't bother with a change of clothes. We just take some thick long-johns and a thermal top to wear while we sleep. Merino wool is warm and doesn't smell even after days of use. Sadly, it doesn't stop you from smelling.