To ride your bike more efficiently practice with one leg. Riding one-legged forces you to concentrate on good pedaling. Put both legs on the pedals, but let one go limp. At the bottom of the stroke pull up. This will better distribute the work load to your major leg muscles.
If you feel like you're in a rut, try something new. Try a different workout or a different program. Your boredom may be the result of the methods you are trying and you might just need something new. Switch up your fitness routines and you might discover something new that you enjoy.