The ollie is a skateboarding trick where the rider and board leap into the air without the use of the rider's hands. It is basically the combination of popping, sliding, and jumping on the skateboard all at the same time. Originated in vertical skateboarding, and later on flat ground, it is not intuitively obvious how the liftoff is achieved, making the movement visually striking.
There is no governing body that declares any regulations on what constitutes a skateboard or the parts from which it is assembled. Historically, the skateboard has conformed both to contemporary trends and to the ever-evolving array of stunts performed by riders/users, who require a certain functionality from the board. The board shape depends largely upon its desired function. Longboards are a type of skateboard with a longer wheelbase and larger, softer wheels.
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.