Deep Breathing: This is important to all of these processes and to your general health. It increases your bloodflow, calms your mind, and steadies your heart rate. One good way to do this is to slowly inhale through your nose till your lungs are full but not strained. Then exhale through your mouth to force as much air out as you are comfortable with. Repeat this for 10 inhales/exhales a few times a day to start. You may feel light headed if you are used to shallow breathing. It is due to an increase in oxygen to your bloodstream. Deep breathing should not hurt you. If it does then you should seek medical attention. Practicing this can better your health and help you to relax and focus.
Centering: When we are not centered our mind cannot focus because our concious mind is moving too fast or is obsessing on something else. Centering is good to use before meditation because it helps us to balance our flow of energy therefore allowing us to focus on our purpose. It is also good to do when you feel off balance or stressed. A good exercise for this it to close your eyes and visualize yourself in a calm state and in a place that calms you. Remember to use deep breathing.
Visualizaion: The act of using you senses to acknowledge something that is not in the vicinity at the present time. This is a powerful tool used in meditation, relaxation, memorizing, casting and all day to day activities. When you can call upon any memory in complete detail, or fully sense anything you desire to the moment you think of it, then you have mastered visualization.
Meditation: The practice and definition of meditation differs between cultures. It is basically the act of relaxing your body and slowing down your thought process to allow you to focus on a specific intention or thought. It is often used to look at something that is bothering you or something you wish to learn about yourself. Meditation is not "blocking out" or "stopping" your thoughts but rather letting them come to you and pass on instead of dwelling on each one. Meditation does not need to be for a specific length of time. Some people meditate for a few minutes. There are records of meditations lasting months but there is no current record for the longest meditation. It is an individual thing and you should take as long as you need and are comfortable with. This process can take a lifetime to master but never give up. The more you practice it the better you will get at reaching and keeping a meditative state.
Grounding: After meditation or any process that increases you energy you should ground. It is the act of giving your excess energy back to the earth or to an object/person. This helps you keep balanced. One simple way to ground is to invisualize the excess energy as a bright light flowing out of your body and into the desired retainer or the earth.
Drawing energy from the earth: You must be careful not to draw energy from other people unless they give you permission and you know them. It is not a replacement for rest but may help if you are unable to do so. There are many ways to draw energy, but the simplest I have found is to visualize a bright light flowing from the earth into your body and increasing your bodys vibrations. The colors you choose depend on you and the type of energy you want. Each color means something different to each person. This process is good to do if you feel tired but dont want to sleep, or if you need energy for any workings/activity.
There are many other things you could consider as basics but without these tools you will have a harder time succeeding in magical workings. Remember these are my views and many could argue thier opinions on them.