RE: Energy Before Exercise
Welcome to MT Rachael
ALSO to add to dg's info, the most overlooked factor is your post workout nurition. By ensureing you are eating optimally after your workouts, you will feel much more vitalised the next day when you come to train again.
Make sure you have an adequate carb intake afterwards. Even a small amount of simple carbs will give you some fuel to replenish.
Best time to train? whatever is most convenient to you!