Basic JD Guide to Taking down Bosses
You are with a party (which is recommended, unless you are confident you can solo). Make sure that your party stays well healed throughout the whole entire battle set your settings on the Almagation to 90% and 0 seconds for the HP (Jade Dynasty Gold). For the MP you can either spam it or set it also on the lamination, doesn't matter. Just make 100% sure that you are prepared with at least 500+ potions of HP and maybe about 100-200 MP potions.
As soon as the boss spawns, turn on your almagation and you should do fine. Also on a side note, do NOT go into a boss battle with low level potions (unless of course your armor is amazing and the boss does extremely low damage to you, which I highly doubt anyone in the server can do to bosses at their own levels), you must always go into a boss with the highest level (cheap Jade Dynasty Gold) potions you can possibly get.
There is another party trying competing to try to KS (Kill Steal) the boss/loot from you. Now under this circumstance, it is sometimes difficult to say what to do. It completely depends on the weapons that each party has.
Basically, the boss loot goes to whichever party did the most damage to the boss. SO, I highly recommend you do everything that I explained in Situation A, and on top of that equip everyone in the party with +8/+9 weapons (ethereal is recommended).
Thank you for reading. That is the best description I can give on this subject. Have fun, and do your best.