Hi, I can do an Ollie for 1 month already but somehow my Ollie is always unbalanced, meaning the front nose pops much higher than the back wheel. I understand that this is due to my front foot not sliding up higher, but I’m not sure how to correct it because my foot seem to get stuck after sliding up about an inch. Is it because of wrong technique or lack of calf muscles?

The longboard, a common variant of the skateboard, is used for higher speed and rough surface boarding, and they are much more expensive. "Old school" boards (those made in the 1970s–80s or modern boards that mimic their shape) are generally wider and often have only one kicktail. Variants of the 1970s often have little or no concavity, whereas 1980s models have deeper concavities and steeper kicktails.[7]

In 1977, skate parks began cropping up all over the place, including Skateboard USA, where Gelfand began to spend most of his time. His buddy, Scott Goodman, is the one who gave Gelfand the nickname of “Ollie” and dubbed his aerial lipside the “ollie-pop.” Pictures of Gelfand during this time period clearly show him getting airborne and performing the trick associated with his name today.
Don’t get your hopes shot if it takes you a while to get this down.  Once you know how to ollie, beginner skateboarders you can do any trick in the book with just a little bit of practice.  Once you get this trick down while your stationary, go practice while moving around a little bit, try to hop off a couple of curbs.   You’ll be skateboarding like a pro in no time.  Just keep at it.
A skateboard deck is made up of curved layers of wood that are combined with glue. Then, the skateboard deck is trimmed down to a board shape that is practical. Trucks are typically made of aluminum or other metal alloys. They are made by melted metal formed by a mold and later drilled into the skateboard deck. The wheels are formed the same way, but with polyurethane. They are attached by ball bearings to complete the product.
Bolted onto the underside of the tail end of a skateboard, the tail guard (also known as a "skid plate") protected the tail end from skid stops and other maneuvers that would otherwise wear away the wood (commonly known as razor tail) and decrease the longevity of the tail. Typically made of plastic, these were widely popular in the '80s but their usage quickly diminished with the arrival of two-tail board designs, which became increasingly popular in the '90s.
So the proper foot placement for the ollie is with the ball of your back foot horizontal on the tail of your skateboard.  And your front foot centered on your board right behind the front trucks.  You may find that moving your feet around in different positions are more comfortable.  This is fine,  everybody can learn how to skateboard their own way.
Smile and wave – Feel free to look around at all the other people at the skatepark that stood by and marveled at your new-found accomplishments (all one of them). I’m sure by this point you’ll be picking up roses that are being thrown at your feet, and taking a well-deserved bow as they begin to chant your name. Take it all in, thank the crowd for their undying affection, and then go get a snow-cone. You deserve it, champ.
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
This board is an excellent option for beginners because of its simplicity and durability. The lightly concave design allows for simple turns but doesn’t require the rider to be an excellent navigator. You can start off riding this deck down the street and use it as you learn ollies, kickflips and how to drop in to a half pipe. It will withstand it all and look good doing it.