Do your Ollie, then, instantly after you pop your board, lift your back foot up to meet your front foot. That helped me solo much I improved twice in a few tries with using that trick. And, if that doesn’t help, it’s just a matter of practicing. If you practice a ly every day, you experiment, you will find u r solution. But, try lifting u r back foot high right after u pop 😉
To get higher ollies, I would suggesting resting your back foot on the very end of the tail and the front foot in the middle of the deck to allow for more slide. Popping as hard as you can and catching your board in the groove of the nose with you ankle practically resting in the groove will level the board out in the air. after this initial movement slide you feet back to the bolts on the tail and nose to ensure a clean landing.