in every situation, replace your basic attack with it, lvl 1 costs 8 mana and the cheapest potion will regen more than enough for it. you should also get around 20-30% attribute damage on it, since that will boost the total damage of the skill, the forumla goes like this:
(base + phys damage) + X% attribute
are you spamming bodkin / barbed and crossfire or something lol? the costs for those skills at lvl 1 is ridiculous. or your using critical shot, which is only good for single target.
to sustain sp costs above 20+ youll need lvl 10 alch pots, 15 sp and under can be sustained with higher tier npc pots, but they are huge wastes of silver and are inefficient, anyway.
that tooltip of steady aim is left over and not translated properly.
the only way your gonna sustain your sp costs is by getting more spr, buying better pots or having a diev friend to reduce your sp costs at all times,
realistically the max spr an archer should go for imo is 40. fletcher skills get immensely hard to upkeep at max levels, even full spr builds struggle with 80+ mana costs per cast. most people leave the 0 CD skills lower leveled so it doesnt eat through sp.