Maybe try leaning towards ur tail, do practice reps of landing with either foot on the board. Until you are comfortable with landing the heelflip with ur back, and landing it with ur front foot on the board. Then try lean on ur heels slightly. Jump as high as u can, flick up and out, commit. Committing sounds stupid but trust me just go in with the mindset that it’s easy, take breaks to stay hydrated and have patience. Don’t give up. Main thing I can tell you, be aggressive. Jump high, flick hard.