Any advice on how to prevent stammering and/or blocking on certain sounds or at least how to get out of it?

Any advice on how to prevent stammering and/or blocking on certain sounds or at least how to get out of it? For context I usually stammer on “B” as in boy, “L” as in love, “N” as in November, “M” as in man, and “R” as in red. I also tend to experience blocks on “W” as in when, why, etc.