I wrote up this long reply on Reddit and figured I'd copy and paste it for the blog record. Here is my checklist for increasing PvE damage
Bane weapon (increases damage against specific target type) - +15% damage melee weapons / +24% damage ranged weapons
Powerful Honing Stone - +7% damage increase - applies to both weapons by using one stone
Infused Corrupted/Lost/Angry Earth/Ancient/Beast/Human Coatings - +15% coating only applies to one weapon so need to apply to each weapon
Minor/Basic/Major/Ultimate Combat Trophies - 3/4/5% x 3 (so up to 15% total) extra damage against specific types. Note: ultimate trophies simply combine major trophies together so are still the 5% per trophy increase as majors were.
Equip load also impacts damage
Light equip load = 20% bonus damage
Medium equip load = 10% bonus damage
Heavy equip load = no bonus damage
Runeglass gems on armor (not recommended; too expensive and you swap gems all the time for mutations - but noted here) - +2% per gem on armor; so in theory +10% damage increase if on all armor pieces
Runeglass gems on weapon (also not recommended; expensive but unlike armor you rarely have to swap your weapon gems so it is at least OK to invest - though a regulary gem is more raw damage %) - many of the runeglass gems can apply a damage over time (DoT) ability so for some builds this can be a net gain in damage
Make sure damage attributes are maxed; eat max level food and you should be getting to a total of at least 500 attributes.
A common split for newer players is 300 in your main damage skill and 200 in CON.
Then over time you reduce CON and keep pumping damage attributes as you get comfortable with not dieing.
The end end end game is to be in the "5 CON club" where you have no CON other than the base 5 and all 500 invested into damage stats. Glass cannon.
Maximizing damage is also dependent on enemy type, weapon type, skills, and right gem. I recommended the top PvE build site: https://pvebuilds.xyz/ -> they've done the math / work to figure out the best builds to max damage + right gems to use for the right situation. For example; it may not be obvious to use a diamond in your hatchet against Angry Earth but mathematically it is better.