My mom got a great idea from www.theideadoor.com for Visiting teaching. And I love it!
Here's what you do: buy your sisters a 5x7 frame from the dollar store. print out a quote/scripture/thought from the visiting teaching message. give to your sisters when you visit them. THEN every month, they will have a new "picture" to put in their frames to display and remind them of the message for the month!
You are more then welcome to steal the ones I do each month! Or feel free to MAKE YOUR OWN or visit www.theideadoor.com for their ideas!
(ps i didn't crop this pic myself this time, sorry.. so when you upload it, on your site of choice, to have it printed.. just make sure you crop it yourself/center it for a 5x7)