*waterproof mascara will make your extensions fall off, use a water based mascara if you must
*there are certain mascaras available that are made FOR use with eyelash extensions specifically (yay!) Try Noir mascara by Blink.
*try to apply the mascara more on the tips and avoid the base. It becomes difficult to clean your lashes if you avoid hard to reach areas.
This and more information about proper care and maintenance of eyelash extensions can be learned in our professional training course.