This achievement will be a lot easier if you have a friend to help you out. Special Ops in general is easier with a partner. The ones that I finished for this achievement are:
The Pit: I beat this one with a friend. Here's the strategy we used. One person focus on half of the enemies and the partner will focus on the others. This way, there will be less time spent hitting the targets in each area. Always sprint. Never reload, switch to your other weapon. Use pistols (I used an M9 and UMP .45). If can, try and hit 2 targets at once and NEVER, EVER HIT CIVILIANS.
Sniper Fi: This one was slightly challenging. Again, a partner would be good for this. Try and stay prone or crouching for most of the time. Always cover the ladders and use the predator drones as efficiently as possible. Watch out for snipers on your left on a helipad, because they have a great view of you, even if you're crouching. If you're facing one way, try and set claymores behind you (Again, a partner would be better, because both of you can guard you're own sides). The easiest way to kill them is actually as they are coming up the ladder, because they are completely defenseless.
Evasion: In this one, again, a partner would be good because you can take the patrols out simultaneously. If you're doing this solo, I would advise against trying to kill the patrols because unless you kill them both, you will start an alarm. If you stay in prone, the guards aren't looking directly at you, and you stay near the sides of the map, you won't be seen, even if they are right next to you. Also, try and stay in the bushes as much as possible. I found a path that you can take without killing anybody. Start on the right side of the map and go prone in the bushes. A patrol will come with flashlights and start looking around for you. let them pass, then start walking up. Stay in the middle. A guard and a dog will pass by in front of you. After they pass, sneak around the three guards to your left and start heading for the left edge of the map. This part will have two guards standing right next to you. Stay prone in the bushes and start crawling up. At one point, there will be no bush to cover you. Don't worry about it and just focus on moving forward. Later, there will be another guard with a dog standing about 10 m away from you. Again, stay to the left and keep moving forward. Eventually, you will reach a fork in the road and on your right, there will be 3 logs. In front of you will be 2 patrols, let them pass. Then, take a right and keep crawling. After you reach the last log, take a left and crawl as quickly as you can to the middle of the fork in the road. After you reach the bushes, again, crawl over the road to the far right. If you do this carefully enough, you won't be seen by the patrols on the road. Keep hugging the right side of the map and you will come to another fork in the road. Take a right and, again, keep to the right side. The one path you can take to finish the mission will be guarded by two guards. Just slowly crawl past their right side and they won't see you. After this, you will see two more guards standing on a hill. These two you can shoot. Don't worry if you don't kill them both. If you're close enough to the hill, just run up and slide down and the mission is complete.
Suspension. Play this one very conservatively. You have a wide variety of weapon choices in the beginning. I chose the ACR Grenadier with ACOG. Just stay behind cover and take out all the enemies. After you take them out, move up a bit and more enemies will come down. Back up again and take them out again. This time some of them will have Strikers. If you want, use one of their Strikers to take the rest of them out. Then, move up. After you cross the broken part of the bridge, pick up an RPG. Then go back down and hide prone behind one of the broken steel beams. A chopper will start coming at you. It will get closer to you, then it will hover above you. This is when you use the RPG to take it out. Now go up again start taking out the enemies. Also, keep moving forward. Try not to get pinned down. Return as many grenades as you can if you're close enough and blow up the cars the enemies are hiding by. Also, if a car is on fire, get away from it because it will explode.
Race: This one is actually in Bravo. All I can say for this one is just keep trying. If you don't slow down, don't hit corners, and don't hit any trees in the end ramp, you will get it. Just try a few times, and eventually you will get it.
Hopefully this helps!