DR
Don't rely too heavily on GPS/GLONASS, always know your position when flying without constant referral to the magenta line. Look out of the window and consult your chart often, and compare ground features and chart.
A couple of weeks ago I flew o/h Aberfan to take some aerial pix for my wife (a project with her school kids for 50th anniversary). On the return leg to EGBO both SkyDemon on iPad mini (blue-toothed to GDL39) and my Garmin GPSMAP 695 malfunctioned for about 15 minutes, no signal, frozen screens. I always, as a matter of principle, maintain a regime of knowing my position by a combination of DR and pilotage. Also if your aircraft is equipped learn to use radio navigation aids such as VOR/ADF/DME. In my case I was tuned in to BCN VOR/DME
When you pass your skill test don't give up on DR/line drawing on charts/whiz wheels/pilotage but continue to practise often. You never know when, all else fails, it could just get you out of a sticky situation