First, being physically tired helps you to clear your mind more easily. This can be accomplished by doing some kind of physical exercise before meditating, or by choosing a time of day you tend to be more tired. Instead of trying to fight the urge for a sugary snack or caffeine boost, use that time of day for a few minutes of meditation to help recharge you. For me the time of day that I feel like I need a recharge is late afternoon, around 3 pm. Meditation has significantly helped me to not only get through the afternoon slump, but to feel anew afterwards.
The second technique that helps me clear my mind is focused imagination. Here is one I used recently. Try it out and see if it works for you!
Picture love flowing like a waterfall into your heart, flowing down through your body and into the ground. Picture that energy traveling through the ground and into all the plant life around you, inducing more growth and life. Now picture that energy flowing back out of the plants into the air, through your nostrils and back in the waterfall entering your heart. The cycle of love and life continuing.
Here’s to being the master of your mind, friends! Happy Meditating :)