These are useful but the best way to get better at public speaking is to do more of it. Don’t spend all your time reading about it. I want to add two more tips.
One of the fastest and least expensive ways to work on your speaking skills is to join a Toastmasters Club. Toastmasters is an international organization that started in Illinois, in 1905 for the sole purpose of helping people (young men at the time) improve their speaking skills. Today Toastmasters has a network of 15,400 clubs in 135 countries. Odds are there’s a club in your area. If not, you can start one.
I’ve attended several Toastmasters meetings. Each club is run by the members and follows a similar format. The clubs meet weekly and you are welcome to come to any meeting and observe. After you join, you decide when you are ready to participate. Your first prepared speech is the ice breaker. It’s a short presentation that gives your fellow members a snapshot of who you are. You progress at your own pace with the support and structure of the group.
I recommend another strategy for those who want to be able to “think on their feet” or speak spontaneously and confidently: Improv. An improv class is fun, and a very supportive way to push through the fear associated with public speaking. Do a web search for a class in your area. You will learn that everyone feels a degree of fear or nervousness around public speaking. So what? You will learn how to move beyond the fear, do it anyway, and enjoy yourself.