Another way is to take a few deep breaths and then concentrate on maintaining a steady breathing pattern.
When you feel relaxed, take a card and look at it, then close your eyes and imagine the card getting bigger until it's the size of a door. Step through the door into the card itself. Note any impressions you get. If there are people in the card, try striking up a conversation with them.
When you are ready to return, step back out through the card once more, let it return to normal size and then open your eyes.
Get up and do something afterwars to ground yourself. Stamp your feet and maybe have a cup of tea.
Michael