Article by Arthur Bosh
In meditation, you should remember two things. Breathing in your diaphragm is the first thing. You will breathe in your diaphragm to make your breath pass through the upper chakras. The second important thing is to stay grounded. Always attach your body to your physical self throughout meditation.
You may try grounding visualization once you feel light headed or spinning or floating. See yourself with roots of light growing out of the base of your body and your feet. They grow stronger as they deepen down into the earth, through the floor of your home, soil and rocks and lava. Certainly, it will cover the whole earth