Champion's fervour is tracked by the five boxes left of your base hotkey bar at the bottom center, on top of the round combat state indicator. For each point of fervour one of the boxes will turn red. Hunters will track their focus at the same spot.
While the gauge is there, with practice you do not need it. As you fight, you will learn that (for example) wild+swift + fervor stance pip will unlock brutal strikes, so you begin to form combinations that unlock and use pips without watching the meter.
Also, your fervor using skills will grey out if not usable, and color up when unlocked. You can glance at the skill icon to see if it is ready if you like that method.
At higher levels, depending on your traits and gear, fervor can become erratic. Several class traits give extra fervor when you crit (which happens a lot more at higher levels), or cost less, and you get them after each kill once you get red haze, etc. While the memorized combos always work and will serve you well forever, you have to watch the bar or the skill grey out at least a little bit to burn off the "extra" pips at higher levels.
"stack all the morale you want but dont come on here wonderin why you aint hittin hard! "