What are some best ways to improve speaking skills, vocabulary and voice tone?

Answer 1

One time-tested method that works for many is to join the nearest chapter of the Toastmasters. Their clubs are there to help you improve all of the skills you are asking for help with. They will start you right off speaking extemporaneously (that means more-or-less "off the cuff") about a subject of your choice - something you love and know something about.

Another thing you could do is act. A school play would prepare you well for speaking in front of an audience.

Finally, I recommend podcasting for someone who is willing to practice regularly, and who has a subject or two that can be discussed over and over again in different ways. Good luck!