I don't think that a fortune teller knows that luck is going to come to you because she can say that you're going to win with this and at the same you lose with the same thing.
Different fortune teller have their methods for telling about people fortune, predicting about our fortune using stars while other taking the help of our palms lines. While some that the advantages of religion view. But I think there is no reality in such prediction about our luck in advance because most of the time their prediction proves as wrong.
For gambling, i don't think it's reliable to consult fortune tellers
That must be a good practice, we cannot be sure about predictions made by some people for our future. Mostly it will not work as they foretell. If they are really capable of foretelling, they would have earned by this time.
Gambling is basically just random results and nothing influences the outcome so we really won't know if we're going to win or not
When we are ready to accept this truth, we will never go for struggling with gambling. If we accept then we will get maturity to accept what ever results that gambling will give.