If you have played previous Call of Duty games on Veteran, this shouldn´t be a problem. Alot of the sequences in the game is about stealth or involves set pieces. There are only a few areas that can be a bit troublesome.
Whenever you suffer damage – take cover! Stay in cover until your health has fully recovered. Always play it safe and don´t take chances. Pick the enemies off one by one and take it slow. Luckily checkpoints are plentiful. Use the riot shields whenever they are available – this is by far the best weapon on Veteran difficulty. You can run up to every enemy and melee them. This is especially useful during mission 14: Prison Break and mission 17: Countdown. You can complete the campaign in about 6 hours, even on Veteran.
When you start the game and continue your Veteran run, pause the game and make sure that you are on Veteran difficulty. Some players have reported that the game switch you back to Regular difficulty, when you continue your campaign.
PART 1:
MISSION 1: Strike
MISSION 2: Kill or Capture
PART 2:
MISSION 3: Wetwork
MISSION 4: Tradecraft
MISSION 5: Borderline
MISSION 6: Cartel Protection
PART 3:
MISSION 7: Close Air
MISSION 8: Hardpoint
MISSION 9: Recon By Fire
PART 4:
MISSION 10: Violence And Timing
MISSION 11: El Sin Nombre
PART 5:
MISSION 12: Dark Water
MISSION 13: Alone
PART 6:
MISSION 14: Prison Break
MISSION 15: Hindsight
PART 7:
MISSION 16: Ghost Team
MISSION 17: Countdown