Basic info for Sin players.
Stats:
You should always sim your character whenever getting upgrades. But this is a good stat weight starterpack. When first gearing up - Haste/Agi > Crit > Mastery > Versatility. Once you get upwards of about 17-20% haste, crit/mastery/haste become roughly equal.
The reason haste is so important is not so much the attack speed of your weapons (though that adds more than you think), but the ticks from your dots happen much faster (more ticks, more energy, rotation feels smoother)
Talents:
MasterPoisoner / Elaborate Planning - EP is generally better in most circumstances.
Subterfuge/Master Assassin: These are basically equal. MA generally pushes single target a bit harder, but Subterfuge provides nearly equal dps and gives you with more options (particularly in M+ dungeons).
Vigor: Vigor is really the only option in PVE right now. But Deeper Strategem and MFD can become quite good in PVP.
Cheat Death: Best for PVE, though Elusiveness can be really strong on some fights.
Internal Bleeding, Iron Wire, Prey on the weak: All are pretty strong. I’d lean towards Iron wire or Prey on the weak for PVE. IB is not far behind and is really strong in PVP.
ToxicBlade, Exsanguinate: Both are really strong. Toxic Blade is your go-to for PVE, however (provided you have subterfuge/shrouded suffocation, and decent haste) Exsanguinate can be super strong in M+.
Poison Bomb, Crimson Temptest: Poison bomb is the go-to in most circumstances. Good single target, helps with AOE too. If you know you are going into a heavy AOE fight (where mobs are up most of the time, or mobs need to die around the same time [bolstering weeks] - Crimson Tempest becomes to the go-to.
Rotation:
Look up the openers on Ravenholdt .net - they are pretty spot on (at least for the opener). After the opener, the priority is to refresh bleeds around 6 seconds or less remaining (unless a bleed is empowered by subterfuge/exsanguinate). Use toxic blade after freshly applying bleeds and get in as many envenoms as possible before needing to refresh.
When you have at least 3 mobs present, Fan of Knives becomes your builder instead of Mutilate. Then just apply rupture to at least 3 targets and then focus a priority target.