Whenever I try to make my mind stress free cautiously, I could see it going much out of control. So I just live it to that.. let the mind wander wherever it want.. And I will have my eye upon that wandering mind. So once it is relaxed it will be back to me..
If you actively try to control your mind, it will resist. Instead if you give up control, give your mind space and just watch what it does, it will cooperate.