A skateboard is moved by pushing with one foot while the other remains on the board, or by pumping one's legs in structures such as a bowl or half pipe. A skateboard can also be used by simply standing on the deck while on a downward slope and allowing gravity to propel the board and rider. If the rider's leading foot is their right foot, they are said to ride "goofy;" if the rider's leading foot is their left foot, they are said to ride "regular." If the rider is normally regular but chooses to ride goofy, they are said to be riding in "switch," and vice versa. A skater is typically more comfortable pushing with their back foot; choosing to push with the front foot is commonly referred to as riding "mongo", and has negative connotations of style and effectiveness in the skateboarding community.
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.