IMHO, there is a huge difference between 3 hrs of productive fishing and 10 hrs of non-productive fishing.
Only increased knowledge of the lakes structure, cover, food source(s) and how everything relates to time of day and weather will you be able to decrease your non-productive fishing time.
Sure, time on the water will help decrease the non-productive time over many hours of casting where as Google Earth, Topo Maps, and the Food Source(s) Knowledge will speed up your productive fishing times.
Many professional anglers spend their practice days checking areas they have identified via options above without ever making a cast. You can be guaranteed they are looking for a food source and what food source it is!! @Catt