Think and Express in the other language

It isn't easy to me. My English is very very poor, especially in so-called vocabulary. For example, the word " show" means performance, an action to express, indication, an event to demonstrate or illustrate...etc. I may only use "show" in my essay, my talk, my dialog, or my webblog. Why? There are so many synonyms about "show". You can not always type show show show show in your stuff. It is clear that my brain capacity is not capable of memorising lots of English words. Otherwise, I really really hate to memorise all day long. I should search an alternative to adapt or overcome this awful situation. I may have a long long road to crawl.