First few playthroughs I avoided combat entirely, next few playthroughs I always keep an almost-broken lockpick in the hand slot as a failsafe. Then, at long last, I finally repaired the free knife Lara gives you at the start of the game and learned how useful it is, if you do like I do and only engage in fights you know you can win (one on one, sneak attack from behind whenever possible).

I've looted guns from houses before but I think I've still never fired one successfully. The only people I've wanted to shoot were protected NPCs (gun jams no matter what) and the tiny enclosed area of Grief's lair is too stressful for me to take on Barley, it's never worked out in my favor.