I am having the same problem, so I am going this way.
Choose playable and possible-finish-able campaigns. This is best for a start:
Not matter name, but objectives. The hard one is with dart-guns because freelancer tools will “evaporate” everytime a campaign is aborted. But with zero M’s and no tools, one can do that many times until gets objectives which are possible. Dont forget fiber wire is also stethoscope at med-room.
Pick a campaign with one target, if it is possible. Try to finish.