Altered Time - your #1 World of Warcraft Mage resource!

Hi guys, i really need help. So my problem is simple, i don't know what else to do to increase my DPS. Currently i have 399ilvl (24% crt, 21%hast, 12% mas, 0% ver) with frost spec. On boss in BOD i keep 16k - 19k dps easy, but in DG mythic i can't pass 14k dps overall, already see others mages with ...