I believe you are taking about the psy vamps posts, yes? Well pretty much a lot of witches draw energy from the earth, plants, the sky, sun, moon, water, fire and all that. But some people take energy from other living beings like people and animals, this can cause fatigue, mind fog, loss of energy and in extreme cases, strong physical illness for the target. And psychic vampirism can ruin your social life. I do not recommend it. Using one's own energy can make you feel lightheaded, uncomfortable, sickly, powerless, drained, fatigued etc. So I recommend drawing energy from creation. One way of doing so is visualizing growing roots reaching deep into the earth, so deep that human hands have not defiled it yet. Draw energy up from there. Then, when the energy fills yor body, raise it up to the heavens and let it come back down purified by the heavens in a ray concentrated on you.
Hope this helps.