Tips:

Scaling Effectiveness: The amount of healing increases proportionally with the damage dealt. As you progress through the game, your lifesteal power will grow, making this accessory exceptionally potent in mid to late-game stages.

Near-Death: When your health drops below 15%, the effects of the Vampire Claw intensify, granting boosted lifesteal and 10% attack speed, and also significant decreased cooldown between heals. Take advantage of this by focusing on offense (trying to avoid being hit) while ensuring your survival until you get safe again.
Also: When the passive effect is active, the lifesteal cap is increased to 6HP, even for non-critical hits.

Synergies:

The base lifesteal (3%/4%) is only applied to melee damage, consider using a melee weapon to combine with the Vampire Claw.
Keep in mind that you can still use the Vampire Claw with other damage classes such as Ranged, Magic, Summon, etc., but with 1% less lifesteal power (also, if you are playing in Master Mode, this lifesteal reduction to other classes is very likely to not affect too much, since you already got 1% bonus lifesteal on Master Mode, resulting in the same lifesteal applied if you were playing with a melee weapon on Normal/Expert mode).


I hope you enjoy this accessory mod.