Complete the game on Veteran. This is EXTREMELY easy in comparison to Call Of Duty 4. You can get shot many times and still live but do NOT get cornered. Being cornered will mean your instant death. Take it slow and reload often. Pick up enemy weapons for ammunition and remember: Stealth missions aren't meant for you to be detected. If they find you, it will be a LOT harder. Try to flank your enemies and watch your back, team mates are horrible at protecting you. You need to stay in cover, but rememeber that wooden covers aren't the best because enemies can shoot right through it. Watch out for shotguns as the enemies has many of them and will ambush you. STAY IN COVER, this isn't Call Of Duty 5 with infinite grenades. The enemies only throw one or two grenades at most. Helicopters CAN BE KILLED WITH NORMAL GUNS! It only takes half or so of a LMG and a couple of clips of a normal gun.