Do nothing except what you would normally do.

OLCI and PYOBP if that's what you normally do. If you're going to get an upgrade it doesn't matter in the slightest that you've done these things.

If upgrades are going to happen then they will happen. Depending on how many (if any) on the flight have higher status than you depends on if you will get it.

Smiling at the agent, begging, etc won't work. Nor will choccies - though they might help you get a date