EQUIP a shadow walk ability and see its range indicator. FIRE to begin a brief channel, then teleport to the marked location.
If you cast [E] Cark Cover before casting [X] From the Shadows, you can see the shroud on the map, allowing you to teleport into it safely without being seen.
[E] Dark Cover can be cast through walls. Keep an eye on the minimap while charging as it will show you the location of where the shroud will appear.
This is extra useful at the start of a round to shroud an ult orb or hallway.
Omen's [C] Shrouded Step is great for catching people off-guard from unexpected locations like the top of boxes, corners, and otherwise impossible to cross sight lines.
Never cast this into an open sight line, the recovery animation leaves you vulnerable.
A great way to take an advantageous fight is prepping your entry with a [Q] Paranoia to blind the enemy first.