White scrub top, light blue scrub pants, plain surgical mask, default hair. This is the boring answer and it is also what works on a busy server.
I started Day 1 in a hoodie because I did not realise the spawn outfit defaults to your avatar's clothes. Patients walked past me twice before I figured out they could not visually tell I was on shift. Switched to the scrub set mid-session and the queue picked up within five minutes.
The pink scrub version is also fine but oversaturated — at peak hours roughly a third of the lobby is wearing the same pink combo, so it loses the 'I can see the nurse' read.