It helped me to learn backside boardslides first. Then I started going more and more to the left of the rail. I started going parallel to the rail then the left side until I was thinking I was just doing a board slide. If you are sticking, go a little faster. Yeah it’s scary, but you’ll be fine if you commit

Speed fixes everything. Try practicing on a mini ramp or something small. Helps build your confidence

What I did to fix the problem was imagine I was just ollieing onto a box and not boardsliding a rail or box, just focus on the ollie