The way I used to fix my stutter, and especially certain words I would tend to block on was by, simply put, forcing the word out. No matter how long it took. Your stutter will get worse if you feel worse about it, it will get better if you feel more confident about it. When you're having a conversation with someone and you stutter on a word, don't try to switch sentence or find a different word, look the person in the eyes and try to get that particular word out again. Doesn't work? Try it again. You might get some weird looks and it might take a while, yet it's way more important for you personally to overcome that block/stutter then it it for them to wait a bit while you finish your sentence. I've been laughed at, ridiculed, felt insecure and like I couldn't ever be a social person or do certain jobs just because of my stutter, I've seen numerous speech therapists all with exercises that focus on my breathing. None worked. What did work, and how I got rid, nigh on entirely, of my stutter, was purely confidence and attitude. I forced myself into uncomfortable situations where I would stutter against new people and forced myself through every word and conversation. Eventually you won't care whether they have to wait while you stutter, once that happens your confidence will rise and your stutter will disappear. Sitting in your room practicing breathing exercises isn't going to work in my opinion, what is going to work is to put yourself in social situations, uncomfortable situations. I can't stress this enough. For me the game changer was when I took a job as a door to door sales man. For about half a year I had 200 different faces and conversations multiple nights a week, and I had to convince them to buy a product, all with a terrible stutter. And at the beginning it was horrible. Yet the more I kept going, the more I forced myself through those blocks and stutters, the more confident I became in my stutter. After a couple for months, it was gone and has not affected my life since.