Spec Specific Azerite Traits
The First Dance is the absolute best trait to go for, you need 1 on your gear as it increases your haste and grants you 2 extra combo points.
Treacherous Covenant is a good overall trait that buffs your agility. It’s an excellent choice for sub as the spec doesn’t have any great traits that excel when stacked.
Azerite traits rotation changes
When playing with The First Dance, always make sure you go into your Shadow Dance without any combo points. The extra 2 from the trait plus the combo points generated by your first Shadowstrike will suffice to send you to 5+ combo points, depending on procs.
Recommended Azerite Traits
Sub is a spec that has mostly standalone traits, meaning that they drop in value by quite a bit when stacked. Making them most efficiency when you only have 1 of them.
1x The First Dance is one of those traits, it's mandatory to have, but you only really want 1 of them.
1x Inevitability also drops in value when stacked, but less so than The First Dance.
1x Blade in the Shadows is another one of those traits, which means you’re at 3 traits that are near mandatory to have on your gear at least once.
Then, with 3 traits left, you’re going to have to go with ideally stacking Treacherous Covenent or a selection of Night’s Vengeance, Blightborn Infusion and Dagger in the Back which also provide you with good options.