Just to clarify the difference between Melee Hit & Spell Hit:

Melee Hit:
Assuming 400 Weapon skill...
Against a Level 80 mob, chance to miss: 5.0% / dual-wield: 24%
Against a Level 81 mob, chance to miss: 5.2% / dual-wield: 24.2%
Against a Level 82 mob, chance to miss: 5.4% / dual-wield: 24.4%
Against a Level 83 mob, chance to miss: 8.0% / dual-wield: 27%

Serveral classes have talents that increase the chance to hit mobs with melee attacks:
Enhance Shamans have Dual Wield Specialization - 3 points improves the chance to hit with dual weapons by 6%
Rogues have Precision - 5 points improves your chance to hit with weapons and poisions by 5%
Death Knights have Nerves of Cold Steel - 3 points improves your chance to with with 1 handed melee weapons by 3%
Hunters have Focused Aim - 3 points improves your chance to hit by 3%
Warriors have Preceision - 3 points improves your chance to hit with melee weapons by 3%.

Note - melee attacks can also be Dodged, Parried, Blocked or Glanced Off.

Spell Hit:
Against a Level 80 mob, chance to miss: 4.0%
Against a Level 81 mob, chance to miss: 5.0%
Against a Level 82 mob, chance to miss: 6.0%
Against a Level 83 mob, chance to miss: 17.0%

Most caster classes have talents that increase the chance to hit mobs with spells:
Druids have Balance of Power - 2 points increases the chance to hit with spells by 4%
Druids have Improved Faerie Fire - 1 point will increase the chance of spells hitting the target by 3% when the debuff is applied
Death Knights have virulence - 3 points will icnrease the chance to hit with spells by 3%
Mages have Precision - 3 points will icnrease the chance to hit with spells by 3%
Mages have Arcane Focus - 3 points will icnrease the chance to hit with Arcane spells by 3%
Priests have Misery - 3 points will increase the chance of spells hitting the target by 3% when the debuff is applied
Priests have Shadow Focus - 3 points will icnrease the chance to hit with Shadow spells by 3%
Shaman's have Elemental Precision - 3 points will icnrease the chance to hit with spells by 3%
Warlocks have Supression - 3 points will icnrease the chance to hit with spells by 3%
Note - Misery & Improved Faerie Fire does NOT stack.

Finally - the Dranei Racial Heroic Presence increases both melee & spell hit by 1% to party members.

Hope this helps!

Cheers,
S.