Grip with front toe by dipping the foot in/down. Hop directly up and swing shoulders first, lift knees as they will follow through the 180. As you're 180ing spot/look at the end of the rail as you come around, this will help with staying centered. Land bolts and ride away like a g. It honestly comes with practice. Spend a few days doing backswaps/270's on every rail, urban lips, tubes, boxes, disasters etc. It'll help a ton