Warm ups will vary based on the skills and elements performed in the wod for a particular day.
You need to get the heart rate up and start sweating.
As Kelly noted in one write up:
Ultimately, you will know what best works for you.  But, being that we
are animals that learn primarily from mimicking other behavior, having a
few examples never hurts.
Warm Up: Erin Cafaro-Rowing (Olympic Gold Medalish)
Warm Up: Brian MacKenzie Running Warm Up
Episode 339: MWod and Warmup: Olympic Lifting