DR Nav
indyaachen
The earth is the best and most reliable instrument, it doesn't suffer from precession nor topple.
Having set heading and noted the time; check/adjust the HI against the wet compass then select a good reference feature, well ahead, as close as possible to the horizon. Revise the heading if necessary. The reference doesn't need to be on the nose, to one side will do but keep the relationship constant. You can even use a cloud or cloud formation, it won't change much in the short time you will be using it. Complete your FREDA/LIFE checks or whatever you have been taught.
As you get closer to your reference you will need to revise it. During this time relax, if you maintain wings level and fly in balance then your heading will remain constant and height maintenance will be good. You do not have to constantly stare at the HI. The more you roll or yaw the more you will cause precession of the HI. Not only for safety, though important, having your head up and looking out you will naturally maintain spacial awareness. As light changes so does the look of the world around you which can be confusing. So often the pilot believes they are lost because of this phenomena and air traffic confirm they are exactly where they expect to be.
DR navigation is not about flying in straight lines (although nice if it happens) but rather about flying a constant heading and speed. At intervals, I would suggest never less than 8-10 minutes, calculate any off track and time errors, you have now found the actual w/v. Regain track, check you HI against the wet compass and having done so revise your heading by the value of the track error.
Any club that allows instructors to do their own thing is unacceptable and I have never allowed it. Particularly in a situation where the student must fly with a range of instructors during their training.