Blood
There are many ways to feed from blood. The most popular are, Razor blades/Lancets/Syringes.

Razor/Scalpel Blades - WARNING: THIS METHOD CAN SOMETIMES CAUSE SCARS
Before you even think about cutting someone's skin, please make sure that you know where the arteries are. Cutting one could result in death. I have also found, that it is quite difficult to cut deep enough to cause problems. The best thing to do, if you are going to choose this method, is to buy some blades (Wilkinson Sword are the best, as they come individually wrapped) and use one per person, then throw it away.

Take the blade, hold it firmly, and cut a cross shape somewhere on your donor's body (arms, back and chest(if male) are the best places). You don't need to cut very deep. It is best to cut a cross shape as the cut will stay open for longer. Then all you need to do is place your mouth around the cut, and either lick the blood, or suck. It depends on the donor, sometimes sucking the wound can hurt. It is best to talk it through first.

Lancets
Lancets are small devices that have a needle in one end. Diabetics use them mostly, to test their blood sugar levels. At one end of the Lancet is a needle that can be replaced, at the other end is a button which you press to make the needle shoot out slightly.

To use the Lancet, massage the chosen area, (being careful not to touch the chosen puncture site), this gets the blood flowing. Then, simply position the Lancet over the puncture site, and press the button. Wait a few moments for the blood to form a bead shape, then, as with the blades technique, either suck or lick the blood.

The Lancet does not produce much blood, but it can be better for donors that are a little screamish, or for frequent donors. It also doesn't produce scars, whereas blades, sometimes do.

Syringes - WARNING: THIS METHOD SHOULD ONLY BE USED IF YOU HAVE BEEN TRAINED TO USE THEM!
Ok, so you've read the warning and you're still reading it, I hope you understand that I can't take any responsibility for any damage caused to yourself or anyone else while using this technique!

Firstly, make sure that the needle has been sterilized and that the syringe part is pushed down. Then push the needle under the skin, not straight down, but across, and head for a vein! When you think you have reached a vein, pull the syringe up slightly, if blood appears inside it then carry on pulling up the syringe, if not, take it out and try again. When you have finished drawing the blood, take out the needle slowly, and then cover the opening with a piece of cotton wool, and cover it with some medical tape.

Psychic
The most popular forms of Psychic feeding are feeding from storms and from other people.

Storm Feeding
This is the easiest one, out of the two, to achieve. It can be done in many ways, but I use this method. When a storm is starting, look up to the sky and watch for the lightning. Don't be scared of it. Just watch the Lightning, and with every strike, imagine that the lighting is hitting you, with every strike, imagine a large bolt of energy hitting you. After a few goes, you should notice a difference.

People
This is the more difficult technique. The technique that I use is to focus on your intended victim, not with your eyes, but with your mind. Then imagine that there are streams of energy coming from you victim, straight into you. This takes a while to perfect, but once you have mastered it, you will feed without even knowing it.