Speed is key, the faster you are moving the less friction between your trucks and grinding surface. Second, you don't want to over ollie on to your rail/ledge/flatbar etc. as the downward force works as a friction booster. you want your Ollie to be precise and comparative to the feature you are grinding, lead your front foot onto the feature and focus on your back foot following it in a smooth motion. I find practicing exaggerated nose grinds even at slow speed improves the over all rail feel.

Try it first in a miniramp when you don’t need to do an ollie, it’s super easy!

Speeeeeeeeeeeeeeeeeeeeeed

speed is key and pretend you're a light footed ninja when you're on the coping

Speed and a lower ollie