Call of Duty 4: Modern Warfare/Ambush

Ambush is a medium size level where players can dominate or be dominated.

Be careful of random grenades and grenade launchers, especially early in the game. Either sprint towards your target or remain cautious and stay back.
 * Do not get cheated

Players always look for snipers in the buildings. Use A-COG Assault Rifles or LPD's instead, so you can always use these weapons from shorter distances. Snipers provide easy kills for rushers. Unless you are excellent at sniping, stay away from sniping on this level. If you do decide to snipe, plant claymores to score easy kills on rushing opponents. And always have a back-up weapon for emergency situations.
 * Avoid sniping

There are two sewers that run perpendicular to the ridge that runs through the map. These sewers are great ways to travel across the ridge. You can also plant claymores right outside the sewers to catch wandering opponents. These sewers also provide great cover and a hiding spot when the last man left. They also provide cover from the random grenades flying from one side to the other.
 * Stick to the sewers

Watch out for strategically placed claymores around walls and cars near the building of either side of Ambush. Beware of campers near the back corners of this map.
 * Check for claymores and campers

The best places to throw grenades are down the two alleys on either side of the ridge. This will catch rushers on their heels. Place claymores behind the cars and tanks leading towards the two bombs. These are almost guaranteed kills.
 * Grenade placement

The turrets near the back of the two allies are an easy to take out rushers with either the turret or with sniping (be a good sniper).
 * Turrets are useful

Staying in one spot can sometimes work, but sometimes enemy players can catch on to your ways, so mix up your strategy every other round.
 * Don't stay in one spot

You can almost always get a quick plant at the bomb on the ridge. So if you want easy points, grab the bomb and get 100 XP.
 * Offense

Rush. Plant claymores at the bomb then go get some kills staying back can get boring and the bomb and opponents are on the run.
 * Defense