Just did this with 904 ilvl FDK. Draylock on Emeriss EU.
And here's how:
P1 - I used Prydaz and KJBW. Since you need at least one survivability Leg for this to work, I went for Prydaz over Drapes. It just seemed easier to let it protect me passively, rather than using Drapes at the right time. KJBW was used as an on-demand burst. Food - I used my usual raiding, since I ran out of Bear Tartare. Prolonged power as prepot, but not using during combat. Ancient Healing Potion for very bad situations that can be salvaged. Also consider taking Abomination's Might (credit to @
Ashaeron). There seems to be no internal cd and I had several back-to-back stuns on Xylem, basically shutting off his casts entirely.
1st Frost phase - use your usual burst, just don't use Sindragosa's Fury. First Razor Ice will be broken by your BoS. Second can be broken by SF to get out quickly, for the third one I used KJBW. Remember to use Death Strike every opportunity.
1st Arcane phase - DO NOT RUSH YOUR ACTIONS. You have about 5 seconds to kill the first mage. Remember to interrupt his cast so he doesn't push you back. Get your health back up. Once you're full you have 2 options - either Ghost Walk+AMS straight to boss (remember to stay away from clones or you'll get knocked around and die) or move one by one to boss. If you move one by one you have about 25 seconds till the boss instakills you with his cast. Once you're there you can interrupt his first cast, Death Grip out of the second, then dodge the shadow balls. After that point you NEED to have an interrupt available. BE racial comes super handy here. Once he starts Draw Power interrupt it immediately. He'll blink away, which is why it's important to spam Death Strike all the time to keep yourself as close to 100% as possible. After that blink you'll need to interrupt Draw Power at least once more, so you'll have to eat those Arcane Barrages. This is where health potions comes in, as well as IBF+DS.
2nd Arcane Phase - same as 1st, but try to get to the boss with at least 90% hp. Using AMS here is a good idea generally, since you'll be back frost phase now.
2nd Frost Phase - this is it, the last push basically. You'll have to deal with a mix of abilities here. He'll be spamming Frostbolt and locking you into Razor Ice again. Use KJBW to get out. DO NOT USE SF, we'll need it soon enough. Make sure that at this point your Pillar and BoS are not more than 1 minute away. Do not use them either. Survive using all you got, you won't have to worry about hp past Xylem.
At 10% the fight will stop and you'll be dropped out of combat. This is when you put on your usual(max dps) gear on and eat up. Run to the edge of the platform behind the void mob and pre-pot. Once combat starts immediately DG him to the edge and start walking backwards slowly. Use Remorseless Winter right at the start, but do not recast once it's over. DO NOT BLOW YOUR CDs YET. Once the new boss starts his channeling cast run about 40yd away from it (the range of SF). Once the three ads spawn use everything you have. Burn them down quickly, Grip the boss to you, and keep whacking on him. If he channels for the second time use your judgement whether to stay or to run. Remember, that the black aoe under him will kill you in the matter of seconds.