1st drop: CO/XO should always set a time for first drop, make a red announcement stating it, and POs should stick to it. You can get brigged for launching too early, and plus having a definite time (to make 1st drop I must be on the Alamo by X) is honestly better for all combat roles IMO.
The actual transport: You should be making runs as often as possible - the only exception being if you're onloading tons of wounded or you need a mount a new module. What matters most is
throughput of marines. In transport I normally have an HF2 and I'll send up reports on wounded to medbay, specifically which limbs are missing.
On the ground: If you have 2 PO's in the cockpit one should be on doors and the other on sentries when you land. On LV lockdown all doors, and then open left hatch. On prison I just lockdown the right hatch. Ice and BR don't matter. Once down I just help load wounded/crates/intel before I head back up.
Evac: Probably the most important moment in the whole operation for POs, if it happens. Both POs should be in the cockpit, preferably with the door closed. One should be on the cameras and the other ready to hit the switch when the time comes, the one ready to launch can keep the door open and be looking into the back if they're alone. As evac is happening you can have a PO in the back moving wounded marines around so they're not next to the doors instead of on the cameras though.