Oh great question!!
In no particular order:
#1 Be a great receiver! The great catchers I have had along the way have helped me tremendously with getting strike calls by catching the side of the ball.
#2 Work hard to get low pitches called for strikes. I had a friend write this for my website http://www.coachataclick.com/blog/5-tips-for-catchers-with-low-movement-pitches
#3 Plan between innings! Let's talk about the next three batters, what they did before and come up with a plan of attack.
#4 Know when I need a timeout! Come talk to me and keep me focused when I get rattled.
#5 Let me help you be great at your position. Ask me to help with your throw-downs and pick-offs, do blocking drills with you, toss BP... Whatever you need because I need you!!