This helped me a LOT when I was being coached on rails.
I was told to stare at the end of the rail until I was off of it. This helps significantly
in the learning stages in terms of staying square with the rail, balanced, and riding away forwards. Basically it keeps your weight centered and forces your body to keep from rotating on the rail.
If that doesn't help, you might be having edge pressure problems. Edge pressure/toe crank/scissoring is simply cranking your toe/heel into the rail in order to change the direction you're spinning.
Toe crank for a backside spin:
Toe crank for a frontside spin:
If you want to come off forwards, in your situation you'd want to use the frontside toe crank.
Hopefully that helps
I used to be KaDONK.
I Rip At Perfect North Slopes.
"t-wall will spank you with a pretzel, you naughty butter boy" - P-SEB