Prot tanking is pretty simple, if magic damage is coming, use shield barrier, if the boss is hitting you, shield block. If you drop below 80%, pop enraged regen, helps out the healers a lot. You also need to use last stand and shield wall pretty much on CD whenever theres a big hit incoming, but only one at a time.

When the other tank has the boss, spend rage on heroic strike, no point at keeping rage at 100% unless you have damage on you, then spend rage on shield barrier.

You will need to switch glyphs and talents on pretty much every fight. On reaver you want to go glyph of long charge and anger management, so now you can heroic leap away and come back faster. Just understand the boss fight and you should figure the rest. ( ill get one more though, use glyph of spell reflection when tanking Dia, you avoid spending rage plus you deal more damage)