Put on your soccer socks partway
Hold the shin guard against the front of your shin
Center it over the shin bone
Make sure the top of the guard is a few inches below the knee
Make sure the bottom of the guard covers the lower shin
Secure the shin guard with straps if it has them
Pull the sock over the shin guard
Smooth the sock so the guard stays in place
Check that both guards feel snug and comfortable
Adjust if the guard shifts or pinches when you move