Symptoms after stroke

I suffered a major stroke over 11 years ago and 2 TIAs since then as well.

I have just come out of hospital with a suspected tia twice in the past year but both found I was ok.

my question to the doctor was, why does this keep happening. The answer I got was that these were precipitated after my first stroke. So if I'm tired, I may get another and then another etc.

is there anything I can do to help to prevent these happening again?