Not so much a solution as some tips , I found MW2 FARRRRR easier then MW1 on veteren it really isnt that challenging... The checkpoint locations are much friendlier and the enemy doesnt seem to throw half as many grenades as in the first.
-Most important thing about playing veteren is to always go prone , stomach flat on the ground whenever possible , you will take FAR less damage this way , only drawback is you move a bit slower so whenever you take some damage move around a corner to heal .
-simply advance to a spot in the level near where the enemy is and get down prone and let your teammates mop up the rest of the guys . All you have to watch for then is a guy running around a corner or a grenade.
-Whenever you get the chance to grab the riot shield keep it throughout the level and let your teamates kill them as you flank around the outside and distract the enemies. Dont forget to get on your knees so the enemy cnanot shoot your feet.
-Almost always best to work your way around the outside of the level instead of rushing through the middle
-Whenever you have access to something like a predator missle , abuse the hell out of it.
-If you ever seem stuck try another route or like i said above alot of times you can simply rush ahead once you spawn and get a great position before the enemies can get into place , your teammates usually dont move up until you do .
-I also didnt notice many points where the enemy seemed to continutally spawn until you reached "location x" so alot of times you can sit back kill everything that moves then wait for your teammates to say all clear so you know its safe.
-I think the hardest part i can remember is the safehouse where you have to protect the computer while it downloads the data , there is a table with green ammo containers near all the windows in the room with the cpu stay prone under there and kill the guys as they come in the room , every now and then one guy will stand by the cpu and open fire trying to destroy the cpu so you have to be nearby in case he appears , this is a good spot to use your flash bangs or grenades.
Hope some of these tips help ...