Low ollies: This can happen for a lot of reasons, but the biggest one is that you are not crouching low enough before your ollie, and not pulling your feet high enough after you jump. When you crouch down, try and touch the ground. When you jump, try to hit yourself in the chest with your knees. ​Both knees. Don’t worry about falling. That will happen sometimes – that’s just part of skateboarding! For more help, read the How Can I Make My Ollies Higher? FAQ
To summarize, a skateboarder's feet need to do two things successfully to complete an ollie. They need to provide a changing force to move the board correctly (so that the combined force of gravity and the skater's feet add up to the green arrows above), and they need to provide different amounts of force with each foot (shown by the red and blue arrows above) to steer and turn the board into the right orientation.
4 amazing skateboards in one nice lot. 1. 1990's Tony Hawk Conplete Skateboard, original falcon 3 design. With Rekon trucks and firelite classic wheels. 2. Sk8mafia Lucero deck. Signed by John Lucero. Brand new deck. 3. 1031 deck signed by entire team on a brand new creepy crawl deck. 4. Brand new super rare Big Mess deck with Blast design. This deck is extremely rare and is a must have for any collector. Both the signed decks are personalized to a guy named Jason that owned a skate shop here in Grant's Pass Or. Those guys were on his wall for a long time before he went out of business. If you have any questions or concerns please let me know. Thanks for looking. Steve