It might be that you are 'chasing' your compass readings...perhaps....
You could try picking a point on the horizon to steer for, and then keep the nose of the aircraft pointing at that.
Provided you are in relatively calm air, this should be fairly 'easy'.
If you can trim the aeroplane so that it flies 'hands off' then that is good.
As the aircraft 'settles down' into a steady flight, pointing at your selected point on the horizon, you will find that the compass also 'settles down'.
Remember the compass is 'nippy on North / sluggish on South' and an acceleration on an easterly or westerly heading will show an 'apparent change' also.
Refer to your theory books for an explanation of these 'anomalies' to refresh your mind.
This may take care of your paras. 1 & 2.
The use of the '1 in 60' rule should assist you in calculating your drift, and accurate timekeeping between groundpoints will assist you in calculating your groundspeed.
This should help you with #3.
See how you go......and consult with your instructor.
Good Luck
Cheers,
