A good writer has a good vocabulary — one that is both broad and deep — because a good vocabulary is essential to clarity, power, and precision. If you have a large stock of words, you can choose the most effective word. The more words you know, the easier your words will flow. Improving your vocabulary can come from incidental learning from context, direct learning, or a combination of these.The best incidental learning comes from reading good books and associating with people who have a good spoken vocabulary and written vocabulary.
Direct techniques include looking in a dictionary for unfamiliar words.
Another direct technique is to record definitions of new words in a notebook, which you review whenever you get spare time. You should try to learn at least one new word a day.
These days, the quickest and easiest form of direct vocabulary learning is through vocabulary-building software