If everything was flying fine before the crash, all trims good, I would look at the swash and make sure it is level. If it is not then I would look at the links first. Inspect them and make sure nothing was bent or disconnected. Then I would ensure everything from the top of the head to the swash is still level, in that order. If everything is still normal make sure that everything is free moving (i.e. linkage rods and bearings). Then check the screws and see if they need re thread locked. If all of that passes then I would look at the servos and make sure they are in good working order and still centered. Beyond this is the work of the more experienced fliers on here.