Ok when it comes to boss fights and your about to start, pop blood rage and hit him with a booming shield slam critical strike!
If your dodge, parry, block stats are good, your revenge should be lit up, i use this directly after shield slam, if not I do what i say below.
Now depending on how hard the boss hits, if you have enough rage you might be able to use heroic strike. I spam sunder ( + heroic strike) until i can shield slam again. Every time revenge and shield slam are lit up i use it.
Once 5 sunders are up, i jump straight to my devastate. Heroic strike (if i have enough rage) and devastate, and i continue to shield slam and revenge whenever possible.
If its a boss that hits like a truck, keep shield block up at all times. I start off with a shield slam, revenge and shield block. And from then on out my shield block is always on cooldown while working my threat generating technique list above.
Also chuck a thunderclap up whenever possible and get the other warrior to demo shout.
So here it is again.
Shield slam
Revenge
HS + sunder
HS + sunder (usually by this time Shield slam is up)
Shield slam
Rinse and repeat until you have 5 sunders to devastate.
Usually my tanking is spur of the moment and whats lit up, but generally thats the oder of it that i use. Remember HS is a good rage burner and is used on a separate cooldown. So if you have the rage use it.
Remember there are other ways to generate threat but this is what i tend to use (before bc) and still today.