Grounding skills help orient you to the present to the here-and-now. They are vitals tools to have when you deal with feeling unsafe due to anxiety, flashbacks and dissociation.
Visual grounding utilizes what you can see in your current, actual environment.
One way to ground using what you see is to look around you and name (out loud or in your head) 3 red things that you see. It is important to actually stop to do the naming, so that you are really taking a moment to notice the red thing you are naming, not just mentally noting what you see.
Then do the same thing, looking to identify 3 orange things, then yellow, then green, then blue and finally 3 purple things that you see.
Then check in with yourself, how are you doing? Are you more connected to and in the present moment? Are you in your body? If so good. If not, try something else to ground yourself.
Obviously, this exercise uses the idea of a rainbow as an easy way to remember the skill. If this doesn’t resonate with you, you can find some other way, maybe it’s using black and white objects, maybe it’s using the colors of a flame, whatever speaks to you and will help you remember.