Earnest application, 6 letters
Made an ___ (tried), 6 letters
What an E may stand for, 6 letters
A notable achievement, 6 letters
A series of actions advancing a principle or tending toward a particular end, 6 letters
Earnest and conscientious activity intended to do or accomplish something, 6 letters
Use of physical or mental energy, 6 letters
Easy, and what this puzzle's theme answers literally are, 10 letters