If you can, I think you have to surround yourself with the language as much as possible. Try to duplicate that total immersion experience even though the temptation is to fall back into your native language because it's easier. Talk to yourself in the language, read only books in the target language,  and carry a pocket calculator app on your iPhone or smartphone to look up a word or expression you don't know. And watch movies. Not so much narrated documentaries as much as actual movies. They're harder to follow a lot of the time, but you'll pick up new vocabulary and you will hear and see real life exchanges between native speakers in the foreign language. Watch the movie a few times over if need be and you'll see your vocabulary grow without even knowing it. It works. 

Yes, exactly!. Straight after coming across new words, I will try to make a sentence by using that word 2-3 times then and whenever I have a chance to include that word in my writing. Ever since I started learning languages, I strictly write at least 2 lines daily in the languages I focus on. Besides, it was my resolution to read even a paragraph in those languages on daily basis. Even though I was fed up with this in the early months, it became my daily routine and helped me very much to make my languages which were at a miserable level even better.

ِAs far as I am concerned, reading periodicals and newspapers on everyday basis played a key role in the improvement of my vocabularies. Alongside, I write them down and try to compose any articles counting the newly learned usages/vocabularies in, a couple of times.

Reading and writing can help you to increase your knowledge of the English vocabulary, and always remember that your fluency is relying on the amount of vocabulary you already posses and the rate of speed you are using them