I usually sit or lie down and try to feel all my energy centers. The ones I always feel are the ones in my feet and my hands, then I draw energy up and through my body from my feet up my legs and up through and out my head at the top. Breathing long and slow and holding it in for say 5-10 seconds everytime to get relaxed. This is very calming and energising, and to help slow down your thoughts and internal dialogue you just concentrate on feeling energy and breathing, or just breathing is easy. After a while, 10-15 mins youre whole body can be buzzing with energy already without any assistance, imagining clear white light is good for purifying thoughts and neutralising any nervousness or fear. I pretty much do this every night before sleep, sometimes i go for projection as well if the energy is really pulsing, otherwise i usually just end up lucid dreaming. But doing this before going into DMT space is a perfect preparation.
hope it helps.