For your repair badge, go commander (else you get bored) on a map where your UAV, Arty and scan are all close together, and pref at a non capturable base (Oman is good, MEC side). Then all you need do is wait for an enemy spec ops to come along and blow all your crap up, then go fix it.
For any combat badges, as said allready, just use a vehicle. Personally I use a bomber cus its fairly easy to get 40+ kills a round using the bomber which is good for basic, vet and expert badges.
for the exp ord badge, the easiest way is the exploding jeep way. I find dragon valley good for this, go china, spawn at woodyard, chuck 3 packs on the front of the jeep, drive it towards the nearest US flag (hopefully they have the base that spawns teh AA vehicle, forget its name, down the road from woodyard on the same side of river) find an apc, aa vhicle, infantry... anything but a tank cus they kill you too easy, drive full speed straight at it, dive out at full speed let the jeep run on up to the target and press the button, which will kill whatever it is and leave you with about 1/2 health left to go suicide someone with your remaining 2 pacs of C4. Personally tho I got mine (basic one) using AT mines on kubra dam, mining the crap out of the road from the US base. This requires that the entire US team are dumbasses tho.
Knife badge aint too hard either, can either do it on Sharqi, the construction site are being a good place cus its usually full of snipers an dtheres plenty of cover. Or you can do it the gay way, and go commander, locate the enemy commander using scan and the O/H zoomed in map view. So long as he's actually camping somewhere out of the way and commanding all you need do is drive to him and stab him in the back 7 times.
Pistol is fairly easy on the city maps, or you can go sniper, get a body shot with the M95 leaving them with 2 bars health and just spam fire the pistol in their general direction.
For any of teh harder badges try and play on a large map (which you can filter in the search) that has a limit of < 40 players. That way the rounds will last ages giving you plenty of time. ones such server you can find by searching for "www.online" which is the server I play on :-)
Sorry for long post, just bored and killing time.