Go easy on the fast travel at first, fast travel packs are limited until you buy an unlimited one. Don't get cocky, even the weakest machine can 2 shot you, especially early on. Spend time upgrading your salvage capacity. Don't buy any weapons till after you enter the bad guys territory, you can buy the best of each weapon from almost every vendor and it really doesn't take too long. Take your time to learn different strategies for each large machine, and always review them when you unlock a new weapon/ammo type. Shadow precision bow is god.