I have to face the similar situation as yours. Here are some my some experiences on how to overcome such situation.
1. Don't try to remember a certain phrase or a certain word by repeating it. It is just a time wasting. The reason is, first, there are tons of new words you will find; second, a certain word has many meanings in different situations.
2. For a certain topic, read as much materials in English as you can. Here is a my experience to read the materials about the White House. First, I read the articles about the history of the White House. Then I read the articles about the structure of the residence, of the west wing, of the east wing. Also I read many stories happened in White house. You can imagine, when you try to describe the White House to your friends, many words and phrases you have learned when you read the materials about the White House.
3. Do some research. When you try to express your thoughts, if there are some words which you have no confidence, don't let them go. It is the chance that you do some research to make a solid memory within a little short time.