Tip # 1 - Launch the first sound
Even though we often stutter in the middle of a phrase, a speech impediment typically begins with the first sound.
Let's take a couple of phrases. The first phrase for us is "What time and where do we meet tomorrow?" In this phrase, the very first sound might be hard. "Where," "do," "meet," and "tomorrow" also can create difficulty.
So, my general suggestion is to work on the first sound in a phrase. That's where we want to create the airflow for our speaking piece.
A great exercise is to get tense and relax on the first sound giving yourself time and putting power back as you have relaxed. In this exercise, we turn tension into relaxation and put power into our speaking.
Another phrase that I suggest to play with is "Actually, I don't know where we meet tomorrow." In this case, "actually" goes as a filler word we often use to kind of create fluency in our speaking. Such filler words don't require much airflow so we tend to use them frequently.
What in fact happens - we say "actually" and stop the airflow. We create the foundation for our stammer at "I don't know."
In this case, we also want to start with the first sound. We want to put a bit more substance to "actually" to create a powerful airflow for the whole phrase. If we stop the airflow after "actually" or "I don't know" that's not a problem. In this case, we want to launch and put a bit more substance to the first sound in "I don't know" and "where we meet tomorrow."
In any case, we want to take full control over the phrase right from the start. And re-establish that control in every speaking piece.