See how you speak ...

Recording yourself is a good way to see how you speak, but you might be shocked to find that your voice when reading and your voice when speaking, unless you often read aloud, are rather different.

Try reading speeches while pronouncing them as though speaking to someone you know.

Read aloud, too. It helps. And try create videos for something like YouTube. It will give you the nerves of a live speech to work with.

Work, also, on speaking slowly and clearly and on creating a set rhythm, as speech is naturally like music.

Practice breathing right.

Public and interpersonal speech benefits greatly from practicing speech and hearing your own voice. It will lead to natural improvements just by you hearing yourself enunciate your points.