I have/had periods where I would stutter more on certain words or letters. I've come to the realisation that for me, that is because I start to notice it and then make it a problem in my head. I get nervous thinking about saying the word because I don't want to stutter on it and then I stutter. That convinces me that word is difficult and that makes the problem even worse. My biggest piece of advice would be to think about it as little as possible, and as like any other word.