It's not difficult. For regular targets, I usually don't bother with the fancy stuff, but for the elites or bosses, make sure to start with your burn abilities first (aka damage over time) and then your longer cooldown, high damage abilities, then go to your slash/strike rotation until your long cooldown abilities are close to ready and start the process over again. Just be sure to have enough focus to use those long cooldown abilities.
If my centering is built up before the fight, I usually pop Zen when I'm ready to start my slash/strike rotation and just slash until Zen is up (Shii-cho form) and then start building focus again.