There are many suggestions above, but the key to your problem is in adopting some of the numerous alternatives and beginning today. It won't be easy initially, and you will get disheartened and disappointed at times. However, if you devote a fixed time and have a clear plan in mind, you will soon notice the improvement and be motivated.
Practical Tips for Improving English Communication
Here are a few practical tips for your ready reference:
The first step is to talk only in English. Never mind the stammer, the long pauses when you fumble for the right word, and ignore the laughter of people when you use the wrong word or mess up your pronunciation.
The simultaneous step is to read as much as possible in English. There will be many new words that you will come across. First, attempt to derive the meaning by reading the whole sentence. Then confirm your understanding by checking in a dictionary. Many words in the English language can have more than one meaning and can be used in various contexts. For example, "eye" is also used to refer to the small opening in a needle through which you thread it, or "bark" is also the outer covering of a tree.
Whenever possible, move around and interact with people who speak good English. We often pick up incorrect words or pronunciations or slang simply because we interact more with people from a similar background to our own who might be as weak as us in English.
If you want to improve your vocabulary, you must try not to repeat the same word in the same sentence or subsequent sentences. Use synonyms of the words. Use a Thesaurus for the same. When making notes in college, you can attempt to paraphrase the lecturer's statements and use your own words to write it down.
You are welcome to also read the following Inspirational Blogs that contain a wide variety of words and will definitely open your eyes to the richness of the English language while also motivating you:
-
www.actspot.wordpress.com - Daily Inspirational Blog
-
www.poweract.blogspot.com - Weekly Motivational Blog
Best Wishes.