Get Focused Shot ASAP
This is probably the best and most valuable skill you can get in Days Gone, so I strongly recommend that you get it as soon as you earn your first skill point.
With Focused Shot, you can hit the R3 button while aiming to slow down time, giving you a chance to line up a headshot for an instant kill. This is an insanely good skill that can let you win most firefights without taking too much damage.
With how iffy the stealth can be in Days Gone, Focused Shot gives you an incredible advantage in all-out firefights, and will make it a breeze for you to get past most encounters.
If you take the time to clear out NERO checkpoints, you’ll also be able to upgrade your Focus meter. As you level up, there are a couple other skills that will improve Focused Shot, such as the ability to reduce the cooldown timer for it, or pausing Focus entirely whenever you reload a weapon.