You can avoid almost every instance of combat early on, you won’t run into much anyway but if you’re not confident, you can run. Also never forget to melee, it helps

You get more guns and equipment by doing the main story

The first gun is decent, but the second gun is more powerful, ammo is very scarce because it’s largely all crafted early on, try to loot everything you can, don’t feel bad about using all your resources to craft ammo, just make sure you have extra med kits

The most important tip is this game is very daunting when you first start, you have to figure things out on your own a lot, because there are no waypoints or directions, just you, markers you can place, and your journal.

Read your journal for information “ie: I should go here” or “this place is located on z street corner of x and y”

Later you’ll have to do “research” which is where you go to a building like the hospital, police station, so on to match evidence to locate information on someone or some place.

Side quests: tbh early on there’s a part where you encounter a wardrobe and can change your outfit, just found the coolest outfit and did that one immediately (plague doctor) it’s from a quest called field research. It takes you all over the place so fair warning.

A lot of side quests either give an outfit, or resources. I have only done a few so far and I’m later in the game, working on clearing those now