Some general tips:
Use hand of sacrifice to dispel cc from your healer. Don't waste it on dispelling frost nova from your DK buddy or something.
Hand of protection can also dispel things like blind from both you and your teammates, so keep that in mind.
Teach your teammates to call for freedoms when they need them. You can use freedom to negate the DK frost stun (the one that stacks on everyone around them before stunning them for a few sec) before it goes up.
You must learn your teammates's defensive cooldowns and teach them to call for hand of protection when they need it. If you don't communicate, you'll often end up HoP-ing a dispersed priest or iceblocked mage or w/e, thus wasting your HoP.
Use your freedom wisely. The new glyph of freedom lowers the duration of any cc on freedom target + the next cc cast on them. So if you see you or your teammates (especially healer) are getting chain cc-ed, freedoming them to lower the duration of CC can be a gamechanger.
EDIT: I personally use a bunch of macros to make this easier. I use simple ones, for example:
#showtooltip Hand of Sacrifice
/cast [@yourhealersname] Hand of Sacrifice
Some people use other types of macros, but I'm used to these and find they work for me in 2s and 3s at least.
Edited by Gigana, 21 November 2014 - 12:24 AM.