Jogging and doing lateral shuffles will help you feel how the shin guards move with your legs. Practicing receiving passes will help you get comfortable contacting the ball while wearing the new equipment.
Scrimmaging is a great way to simulate gameplay contact and get a feel for maneuvers like cutting and shooting while wearing your shin guards. The scrimmages will be good for practicing turns, stops, starts, and other soccer moves with the different feel of having shin guards on.
Varying your moves during the scrimmage will help you adjust to the new dynamics quickly.