Max all skills in 2nd job except final attack (it's bad), with mastery/arrow bomb (it got buffed in new source, now it no longer does weak damage on the 1st mob) /lvl 6 booster first then whatever you find useful. In 3rd job it depends if you leech mostly or not, if you leech you can leave strafe at 1 and max all the rest since strafe becomes useless when you get hurricane and the rest all have some uses
There was this guide with levels and all (it's kinda outdated though) https://royals.ms/forum/threads/fius-somewhat-okay-bowmaster-guide.32068/