Be on the Hunt
Rise of the Tomb Raider is just as much about hunting and survival as it is about progressing through the game’s Indiana Jones-like story. In-between main mission objectives, you’ll often be dropped into open areas that you can explore. It is here that you’ll be able hunt regular and exotic animals, as well scavenge materials from nature. Don’t sleep on this, especially if you want to fully upgrade your weapons or play on the hardest difficulties.
See what you need and head to areas that contain that animal/resource you need (animal types are marked on the map legend). Male Deer, in particular, are fairly common and can drop exotic hides, so be sure to take them out when you see them. Also, once you have Master of the Land, a skill that notifies you when an exotic animal is around, put it to use. Be careful, though, as bears and big cats can be extremely deadly and will put up a tough fight. Be as stealthy as possible in order to reduce the amount of work and chasing animals around that you’ll have to do.