A lot of members from the fraternity have given very valuable suggestions and advice.
To improve your communication: start by reading English newspapers. Read from the first to the last page. Slowly see the difference in the language used to write different sections e.g. current affairs, business, sports; each is written, no doubt, in English, but the grammar, the tone, the words, and the construction of sentences will be different in each section. If you are not comfortable starting with newspapers, then start reading popular children's storybooks like Jataka Tales, Ramayana, Mahabharata. These books use simple words and illustrations to enable children to grasp the words and the meaning. You can slowly move on to reading newspapers and then watching BBC news, English movie channels, etc. While watching the movie channels, read the subtitles and also listen to the actors to know the pronunciation of the words. Forget the story of the movie; concentrate only on the pronunciation, phonetics, and the subtitles.
You talk too much without thinking: Learn the art of listening. Start with someone you trust. Get them to talk and listen to what they are saying. Develop listening skills. If you are tempted to butt in, pinch yourself to avoid interrupting.
Now to address your problem of talking without thinking: Whenever someone asks you a question or your opinion/viewpoint on something, take 10 seconds to clear your mind and put your thoughts together. Then answer clearly and precisely to the point.
Helping others is not a waste of time if they benefit. Besides, my guess is you are doing this because you like doing it. If you don't like doing it, then don't do it rather than saying, "I am doing but not benefiting." Sometimes in life, you do something for your inner satisfaction and not for what you can get out of doing it.
Being from a village is no excuse for failure. I have come across so many people who come from a rural background but are confidence personified. If you aren't confident, then the best way to gain confidence is to watch people around you. Learn how they walk, how they talk, how they carry themselves, and learn those mannerisms. It isn't difficult. Nobody is born with the proverbial golden spoon in their mouth. Everybody learns as they go along. How many of us are born with impeccable table manners? Most of us wouldn't have learned it while growing up. We learn by watching our surroundings, and in trying to blend in with the surroundings, we pick up the traits that are necessary.
I will end with two popular proverbs:
1. Rome wasn't built in a day or for that matter any city, so don't expect results overnight.
2. When in Rome, do as the Romans do. To blend in with city life, learn the traits, and before you know it, you would have blended in well.
All the best!