how to learn all the hand/body signs; how to use these signs while speaking without getting distracted; how to speak without being nervous; how to form coherent sentences while speaking; how to come up with truthful and coherent responses on the spot without thinking; etc.?
Are you talking about formal presentations or day-to-day interactions, like at work or whatever?
In the past, men took care of this. The problem is pride. So a greenhorn would start work at an all-male work place and the men would stomp out any pride the green horn had. Once he was humble, he wouldn't be nervous anymore. Since women have invaded everywhere, that is a lot harder to find.
So you need practice. I recommend joining a meet-up club (like fishing), where you are a complete noob, and practice humility. In other situations push yourself to talk to strangers. Also, watch what other people are doing. If you are starting out, it is better to listen than talk, but practice talking some. I don't know much about Toastmasters, but that sound promising.
1. Learn humility to lose the fear.
2. Practice.
3. Practice some more. This builds confidence.