Hello, as an attempt to contribute I decided to come up with this small tips and tricks for unholy DK thread.
IF this is an repost, please remove this. I couldn't find anything with quick search
1. Lichborne (Can be used while CC'd)
+ Turns you into undead which prevents getting Feared (Also breaks fear)
+ Immune to hex (Won't break it)
+ Immune to polymorph (Won't break it)
+ You can heal yourself with death coils (~18k / Death Coil) (Glyph of Death's
Embrace helps on this since it refunds 20 RP if death coil is used to heal
Macro for healing yourself with Death Coil
Code:
#showtooltip Lichborne
/cast !Lichborne;
/cast [target=player] Death Coil
+ You can also heal your pet with Death Coil
- Avoid getting shackled etc when under the effect of Lichborne
2. Unholy Frenzy
+ You can use this on your arena partner to prevent him from getting CC'd
(Everything that breaks on damage f.ex. Poly / Traps / Repentance...)
3. Ebon Gargoyle
+ You can sacrifice your gargoyle if your ghoul happens to be dead for any reason
+ Controlling your gargoyle might be bit hard but try turning your pet passive and then
spam attack
4.Dark Simulacrum
- The spell you are trying to copy needs to require mana
+ Spell will be instant cast when DS'd (except channeled spells)
+ Dark Simulacrum can't be grounded
- Upon using a copied spell, the cooldown on that spell will ALSO be copied
(obviously only matters for spells with cooldown above 1 min.
+ You can use Dark Simulacrum on another Death Knight if he has copies spell from
another player, the spell will be copied from DK even though it doesn't cost mana
I WILL NOT LIST SPELLS THAT ARE UTTERLY USELESS OR WON'T WORK
Druid
-Cyclone
-Entangling Roots
-Solar Beam
-Star Fall
-Typhoon
-Starsurge
Mage
-Polymorph
-Mirror Images
-Dragon's Breath
-Pyroblast
-Living Bomb
-Counterspell
-Time Warp
-Ring of Frost
-Ice Block
-Blink
-Frost Nova
-Cone of Cold
-Mana Shield
-Ice Barrier
-Invisibility
-Deep freeze (you can copy this, but target will still need to be frozen, Hunter's trap or Hungering cold counts as Frozen)
Paladin
-Seals (Lasts 1min)
-Hammer of Justice
-Divine Shield
-Divine Protection
-Hand of Protection
-Hand of Freedom
-Avenging Wrath
-Holy Wrath
Priest
-Pain Suppression
-Power Word: Barrier
-Power Word: Shield
-Divine Hymn
-Mass Dispel
-Fear Ward
-Psychic Scream
-Psychic Horror
-Mana Burn
-Silence
-Mind Control
-Leap of Faith
-Guardian Spirit
Shaman
-Heroism/Bloodlust
-Hex
-Earthshield
Warlock
-Fear
-Death Coil
-Shadowfury
-Howl of Terror
-Chaos Bolt
-Infernal 
-Unstable Affliction
-Succubus' Seduction
-Felhunter's Spell Lock
-Haunt