Look at where the energy is, like your hand. Without changing focus, move your vision over about 2-6inches to the side. This should make your background vision blurry but keep your hand (seen peripherally) in focus. Keep working with the energy while looking to the side like this. Using your peripheral vision you may begin to see glints of light, sparks, or a fog/haze around your hand. Dont quickly look over at it, or freak out. Stay relaxed and if the image holds slowly move your eyes back over to your hand. Eventually, with practice, you'll be able to look directly at it.
If the energy isn't near anything physical you need to focus your eyes onto where the energy is. To practice focusing on invisible things =) place your hand directly in front of where the energy is and without changing focus, remove your hand.
Beginning to see energy involves training your eyes to focus on the energy (like a camera lens) and THEN you will see it. Unlike physical object that our brains naturally focus on for us.