One of the best ways to find more Shot Clock and Timekeeper volunteers is to teach them how to do it. At the beginning of the season run a "training session" for parents during a practice. Have someone who is proficient with the shot clock and scoreclock teach everyone how, and then give them the chance to practice on their own during the practice. It's a good way to teach everyone and once they know how they tend to be more comfortable "volunteering" to do it.
Usually the local arena ice people will show everyone how to do it if you ask ahead of time. They can often provide you with written instructions about the clock operation that can be distributed to everyone.
Scorekeepers - Filling out a Game Report (Gamesheet):
Time Keepers: Reponsible for starting and stopping the time clock during the game, recording goals scored and posting penalties as indicated by the referees.