So, here goes.
What are Spiritshots/Soulshots used for? I have a lot of each in my inventory and no idea what they are for. They sell for a lot at the vendor though :P
Soulshots = 2x Damage per melee 'hit'
Spiritshots = 1.5x Damage for Spells.*
Blessed SpiritShots = 2x Damage for Spells and Increased cast speed.*
* = Healing spells gain additonal 'instant' heal power and debuffs land easier. No change to actual buffs other than the faster cast from BSPS.
Each weapon has a rating for how many of each shots are consumed to 'charge' that weapon for a single hit. Each weapon is also restricted on using shots that are the same grade as the weapon. For NG, D and C grade weapons use between 1 and 3 shots per charge. The higher the weapon the more it uses. Bows use even more shots. (Up to 10 at max) When you reach B grade weapons, the shot usage drops to 1 on most weapons other than bows. (Bows don't drop back down to 1 per until S grade.)
To 'charge' a weapon with shots, have a weapon equipped and a sufficent number of shots in your inventory. (You should have SS/SPS for Novices from your beginner quests.) Simply left click the shots and there should be a 'spang' sound and a little light show around your weapon as the shot is charged. On your next attack (if it is melee) when you hit the target the SS will discharge in another light show around the attacked mob.
NOTE: You can charge SS or SPS/BSPS at any time, but SS will only be used if you hit something with the weapon/arrow and SPS/BSPS will only be used if you cast a spell. Melee 'damage' skills use SS, but melee 'self buffs' are neither spells or damage skills and recieve no bonus. Thus a LE scout's 'Elemental Heal' benefits from SPS/BSPS but a Orc Raiders 'Battle Roar' does not regen/gain any extra HP or trigger the use of either. The LE Scout patk/pdef self buffs do not use either shots. BUT, the Elven Elders buffs WILL consume SPS/BSPS. (Basically if you can only cast it on yourself the 'spell' will not use shots.)
To use the shots continuously you can 1)Click the shots after each swing/cast constantly (Old difficult way) or 2) Drag the shots over to your skill bar and then right click them. This will make the icon shimmer, and you will get a system message stating that shots will be automatically applied. Shots will be used until you right click the icon again, or you un-equip the weapon. (OR you run out of them!)
Unspent shots that have been 'charged' into a weapon will be lost if not used.
NG shots can be bought in stores, all higher grades must be bought from players who craft them. (Or made using someone elses craft shop.)
There are also 'Compressed' packages of shots. These simply are bundles of shots (Right click to unpack them) that weigh less than if all the shots were simply 'loose' in your inventory. For the most part, the cost to 'package' them is not cost efficient. And buying the store ones more expensive than the 'singles' you can buy in bulk. As such they aren't used very often, unless someone really needs to carry a lot of them into the field. Notably, single shots 'stack' but the packages do not.