Place a hand on the tree
From where you are standing, you need to place your hand on the opposite side of the tree. Make sure that your grip is firm on any of the scars of the trunk.
Place the other hand on the tree
Now you need to place the other hand on the side of the tree which is facing you. Apply pressure on the tree with both your hands as if you are going to squeeze the tree or to hug it. As you move up, this technique will assist you in maintaining your balance.
Squeeze the tree trunk between your legs
The trunk of the tree needs to be squeezed between your legs, while you are placing the soles of your feet against the tree. Press your feet against the tree with some force.
Find the next handhold
While you are using your hands to find the next handhold or scar on the tree, you should stretch your upper body. It is important that your lower body and feet are pushed up against the trunk. As you find a new place to hold your hands, try to affix your upper body with the new spot.
Maintain pressure with the lower body and move up
While maintaining pressure against the tree with your legs and feet, you need to move your lower body upward. If you are a beginner, you would be almost crawling up the tree but this will become easier for you as you gain more experience. You need to repeat the above mentioned steps with the same technique until you reach the desired height.