The first part to becoming proficient in working magic is learning to control your mind. You need to control the inner chatter of you brain and focus on one thing - the magic you're working and the desired outcome.
Regular meditation is the easiest way to achieve this.
When first starting out meditating, it's best to focus on your breathing. Take long, steady and deep breaths. At first I would count "1, 2, 3, 4" or "In... Out... In..." but over time I got over it and I learned to just pay attention to my breath. You can do this in any comfortable position, sitting or laying down, but you might just fall asleep if you're laying dawn. (If you end up falling asleep sitting up, you'll fall over and most likely wake yourself up.)
It's a good idea to set a timer when you're first starting out just in case you do fall asleep. (And you can keep track of how long you're meditating, too.) Smaller amounts of time are best when starting, as they are easier to achieve and it is less likely for you to feel disheartened.
Also, if you're having trouble quieting your mind, just let the thoughts come. Don't dwell on them, but don't fight them either.
Other ways to help with meditating are:
Listening to music. (Preferably without words.)
Visualizing a scene or place.
Doing repetitive tasks and focusing solely on what you're doing.
Stretching - focus on your breathing while you stretch. Like yoga.
Note: A way that I make meditation more spiritual than just about well being or magic is by using it to connect with Deity. I have a place that I go to where I can be with my Patron God/dess and it does a world of good.
(Don't forget to comment with your own suggestions.)
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