I know two methods certain to boost your energy while painting. The first is to paint with a group of other painters. Nobody wants to set up all their gear and then be seen as a loafer… distracted and waiting around for inspiration that isn’t going to come.
The second is to actually be excited about what you’re painting. Sometimes it’s easy. A scene may inspire you so much that you can’t paint it fast enough. Other times it’s difficult to ignite the flame and keep it burning through to the finish. Getting physical is an effective antidote to mental fatigue. Often, I will work large or set arbitrary deadlines for completing the next stage of my painting. It’s amazing what a deadline can do. Stress motivates. It really does. Action is self-sustaining. When you are physically working, your craft, your process becomes its own reward. Before you know it, you’ve turned that blank canvas into something. Don’t jump into self-evaluation too quickly. Be content that for another hour or another day, you were in the game! That’s where it all happens. The swings, the misses, the hits, and the home runs… they all add up. And isn’t creating and working what it’s all about?