Marksman

Marksman gain Status Assessment II, which in addition to showing HP also informs you of damage type strengths and weaknesses. Knowledge on what to use against enemies can be very important and this should be used frequently.

Blast Away is a self peeling tool that knocks the enemy back on a failed save, letting you safely move away from the target afterwards.

Prone Cover is another form of defense that lets you drop prone as a reaction. It gives the prone keyword to your ranged attacks and basic reactions, so you aren't left completely vulnerable while on the floor. You will have to spend AP to stand up again if you need to move, so it's not something you want to always immediately use.

Consistent Shot combined the accuracy of a precise attack with the damage of a heavy attack. Primarily used when you want a high chance of dealing good damage against a target that still has RP remaining.

Perfect Shot can do a lot of damage, but is reliant on your teammates to keep enemies within your line of sight for long enough. If your target breaks line of sight, the ability is wasted. To keep your options the most open, it is best to start your perfect shot by spending 2 AP as the last action on your turn. Now if you can't finish it, you will have only wasted 2 AP instead of 4.