theres some teas you could try, be sure you're not allergic or should not ingest the ingredients before taking them.
a very simple one is to take a deck of playing cards, draw one card [without looking at the card] try to visualize or 'feel' what the cards colour is. say [or write] if it's a black or red card, then flip it over. record if you're correct or not. don't go fast, sit and concentrate. meditate on the card if you must. once you feel ready, move on to doing the same thing but with the cards number, then the suit, and finally the full card. there is an actual deck of cards you can buy with different symbols on it, but playing cards work just as well so don't worry about it.