Which method you use to learn new word ?
To learn a new word:
1 Hear it 2 Read it 3 Write it 4 Say it.
5. Use it in a sentence (6) Repeat all 5 steps over again
I read books. Usually I meet several new words on every page. Its quantity depends on a difficulty of a book. I started with books for children - fairy tales. I read every chapter three times, while I begin to understand it completely. Next day I repeat reading of the chapter. Every author uses his or her own set of words. While you read a book you will meet identical words. So to the end of the book you will know most of them. Also I watch TV shows. At first I read subtitles till I understand them completely. Then I watch an episod. I can watch it several times till I get it.
Learning words in some content - books or movies is the most efficient way to do that for me. Also I'm writing a lot on italki :)
When you learn a couple of new words , make a paragraph using them!
I watch movies and serials a lot. If I see some new word I usually write this word in to my small notebook. Also if I see some new phrase I do it the same way. After I repeat them if I am not lazy. Videos on youtube made by people from engvid.com are very helpful. They give me always many practical advice. I can recommend it :)
Flashcard apps are helpful for me, but it's a good idea to learn the sentences that go along with the words, not just the word and the translation out of context. Otherwise one can end up with a memorized word but have no idea how it's used in the language.