It's not been mentioned so I'd like to add this one: if you decide to save a game in the same area (grid square) as a previous save give it a new name. Otherwise the previous save will be overwritten & you could wind up with a ctd; it's happened to me before.
If you have the community units mod installed that can be a problem. A lot of people, myself included, have had crashes with it.
I've also had it crash when 2 large convoys were spawned very close (within 20-25km) to my position. Fortunately this has only happened once.
Finally, as was previously stated, don't save within 50 km of anything. This includes aircraft too.