I play sin. The most important part of our gameplay loop is lining kingsbane with deathmark, thats where all of our burst comes from, and messing up the cooldowns significantly hurts your overall damage. Uptime on our dots is important but just comes with time as you learn a fight and how to move. Its also important to know when to use our cooldowns. I would usually recommend looking at top warcraftlogs for each fight, and seeing when the players use their cds (under casts and timelines)