Let me start by saying that this has nothing to do with controlling someone elses will. This is about training your own impatient psyche to bend at your Will and to be able to enter trance-like altered states of consciousness more easily.
Peter J. Carroll writes more about this topic in his book Liber MMM, a recommended read and course plan for magickal work! Record all experiences with these activities in a magickal journal of some form.
Try to be still for extended periods of time. Aim to sit or stand in the same position for at least 30 minutes – starting aim is 2 or maybe even 5 minutes. Do not blink, do not move, do not scratch what is itching. You might find your position is getting uncomfortable, but keep at it! Keep doing this until you can do it in periods of 15 minutes or longer, then move on to Breathing.
Concentrate on your breathing, let it deepen, work with your diaphragm and let our entire focus be on your breathing, in and out. Once this can be done in periods of minutes 30 minutes or longer, move on to Non-Thinking.
Train your mind to not actively think any thoughts. This is much harder than it seems as even the most futile attempts reveal the mind to be a total cacophony of sounds and images, hurdling against you. Try to conquer those invading thoughts and let them slip pass you without any notice. Keep the mind empty. When you have sufficiently mastered the basis, move on to improve your concentration.
- Sound concentration
Choose a mantra and repeat it, listen to it inside your head or repeat it loud. Just stick with whichever method you choose even though invading and distracting thoughts will arise and try to break your concentration. Just keep repeating the mantra. The simplest mantra is Aum or Om, but there are several other to choose from depending on tradition and/or religious beliefs.
- Object concentration
Choose an object to focus your attention on and exclude everything else. Perhaps start with focusing on the flame of a small candle held in your hand? The more meaningless and random the object is to you, the better.
- Image concentration
Close you eyes and try to vizualise a simple symbol inside your mind. A cross, a pentagram, a triangle. When you can hold the image without distortion for an extended time, add more detail to the basic form; three dimensions, colour etc.