Do as many of the following as you can:
Eat the highest powerscroll early.
Equip 4/6 casting, 40 LMC and as much Mana Regen as possible: Hat Of Magi (4), Pendant Of Magi (3), Rune Beetles Carapace (3), Legs (2), Arms (2), Gloves (2), Crystalline/Faction Crystalline (3), Faction Ornament Of The Magician (3), Boomstick/Book (3), Tounge Of Beast (3), Lieutenant Guard Sash/Replica (2), Conjurer's Garb (2)... Ankh Pendant Bonus (up to 3 for one hour).
Lich Form. (13 MR... I think)
Shadow Wisp.
120 Med.
120 Focus.
Use 'gas' rooms to kill your Mirror Images while you're in Cat/Dog form when you can gain from that.
Record a Shadow Jump macro in UOA, with the targets changed to 'target relative', to jump 1 tile North, East, South, then West. (So that it doesn't end up stuck against a wall.)
Death Strike a Horse/Cat while unguilded (not sure if you can do this on Siege), you can still hold a Boomstick/Book, if you're human your JOAT Macing/Wrestling will be enough to still hit it.