First of all, you might imagine energy as flowing in a similar way to water or air. Another way to think about energy from a design perspective is: where does your eye wander, and where do you feel drawn? These are hints to the energy flow, since energy flows where attention goes. Also consider that the main gateway to energy in your home is your front door (as I describe in this post).
When getting where you want to go is in any way difficult or inconvenient, perhaps because of furniture placement or items placed too close to doors, it indicates a stagnant or obstructed energy flow. In this case, you’ll want to remove or rearrange items so that it feels easy, breezy, and comfortable to reach any and all areas of the house.