Pull all of the s/plugs out.....
Key off.....
Remote starter switch connected to the starter.....
Compression guage installed.....
Crank it for several revolutions....(you'll see the guage needle climb and then level off somewhat)
Write it down and go to the next one.

I like to attach a battery charger when doing this so the battery juice will stay up.

You might add a few squirts of oil in each cylinder and then repeat the test to see if the readings come up. If the readings go up then the rings might be worn.
called the dry/wet compression test.

The delta should be less than 20% (I think thats the number) between high and low cyl.