First of all, glyph yourself with HT glyph, innervate and WG. Gem Haste/SP or spirit whenever possible. Get loads of mana regen by spirit, and some useful sp. here is the build:
http://www.wowhead.com/talent#0VGzu0hZZfVcui0xbuA0sVo
Use healbot and put HT on your left click and WG on your right click.
Now all you need to do is to cast your 0.5-0.6 secs HT whenever and wherever someone gets hurt. You should run out of mana in 2 mins (if the fighting is intense) or 3-4 mins (more relaxed fights). Then you should use innervate on yourself. It should fill you up with the glyph. And there still is mana pots when emergency needs be. With some practise you should be able to maintain mana/spam rate at about 5 mins before utterly running out of mana. Keep in mind that better gear may improvise amount of that time. Many boss fights have free times that you can regenerate and the time needed could decrease with better the gear you have. Replenishment buff is also crucial. You dont need endless mana or 30 mins of mana pool after all, many boss fights take place between 5 mins to 10 mins at best.