Focus on your breathing. Square breathes help me the most. I would also try grounding, which is: Acknowledge FIVE things you see around you. Maybe it is a bird, maybe it is pencil, maybe it is a spot on the ceiling, however big or small,
Acknowledge FOUR things you can touch around you. Maybe this is your hair, hands, ground, grass, pillow, etc, whatever it may be, list out the 4 things you can feel.
Acknowledge THREE things you hear. This needs to be external, do not focus on your thoughts; maybe you can hear a clock, a car, a dog park. or maybe you hear your tummy rumbling, internal noises that make external sounds can count, what is audible in the moment is what you list.
Acknowledge TWO things you can smell: This one might be hard if you are not in a stimulating environment, if you cannot automatically sniff something out, walk nearby to find a scent. Maybe you walk to your bathroom to smell soap or outside to smell anything in nature, or even could be as simple as leaning over and smelling a pillow on the couch, or a pencil. Whatever it may be, take in the smells around you.
Acknowledge ONE thing you can taste. What does the inside of your mouth taste like, gum, coffee, or the sandwich from lunch? Focus on your mouth as the last step and take in what you can taste.
I hope this helps!