Its really good to hear that you are facing your stuttering and arnt letting it control your life!. As for toast masters i've never done it myself but thhe institute talks about it a lot. There is actually a toaster masters group for people who stutter and i have a couple friends who have had some really good experiences in it. Getting a system and a routine is the most important thing about the program. I know a few people from my class who gave up on doing the practice and now they are back to the way they were before the institute. Just remember that you get out of the class what you put in, as long as you keep up with your practice and stay motivated your speech will improve and you will have control over your speech. For prep there isnt a ton that you can do. You could try practicing breathing using your diaphragm, and also calling the institute and asking them if there is anything that you can do. It is a lot of work, but it is so well worth it. Good luck!