Alexis,

I make a special effort to improve vocabulary, reading fluency, and oral fluency for students in my English classes.

I have a favourite academic web site called Reading in a Foreign Language:  

http://nflrc.hawaii.edu/rfl/

There is a special article about building vocabulary through extensive reading:

http://nflrc.hawaii.edu/rfl/April2015/discussion/nation.pdf

I teach English five days a week to immigrants to Canada.  They are mostly 30-50 year-old adults who have learned English during high school and who are highly motivated to improve their English so they can find work.  

For my lower group (false beginner - A1+), we read graded readers (Oxford Bookworms and Penguin Readers) starting at the 400 headword level and ending at the 1400 level about four months later.  The readers have a matching audio recording.  Students read and listen in class and read and listen at home.  We average one small book a week for a total of about 15 books and about 120 000 words.

My lower group reads at 30-50 words per minute at first and gradually moves up to 80-120 words per minute.

For my higher group (high beginner - A2), we read graded readers starting at the 1000 headword level and ending at the 2200 about four months later.  We average one small book a week for a total of about 15 books and 250 000 words.  

My higher group reads at 80-120 words per minute at first and gradually moves up to 150-200 words per minute.

As an EFL student, I find that reading books or watching videos or movies (about things that i like) helped me a lot with learning new words. I would look for the vocabulary while reading in order to understand what was going on, or I would understand a few words if I watched a movie and I would make sense of what the characters were talking about. 

In order to then remember those words, I'd use them whenever I spoke english (to my teacher, in class, or to the foreign friends that I had). So speaking english also helped me a lot with that whole "how to learn new words" process.

For most learners, they have to well identify what goal they are heading for or more precisely what skills they would like to learn and master. For instance, a person who is just intended to improve speaking do not need spend plenty of time on repeated vocabulary learning. In this case, the learners may not learn many words used in the academic reading and they probably would have difficulty in reading academic articles when they are studying in the university. Primarily academic vocabulary learning may consume much of one's time and effort whereas if a student who is to take formal English exam has to strain their intelligence on vocabulary learning with more efficiency in order to improve their reading comprehension. 

Certainly simply rote learning with no critical thinking can hardly give you a good sense of vocabulary so as not to use these vocabulary to improve speaking and writing. In this case, Lexis is perfectly right that use words learned as more as possible in every condition while you are speaking or writing. Sentence-oriented vocabulary learning is the best way to improve 4 skills at the same moment is the best policy to improve English. 

Surely if you have friends talking to you frequently and they are all willing to help you correct pronunciation, grammar and spelling with "proper" and "pertinent" instruction to improve English in no time, that is worthy of congratulations and a good sign to accomplish English in short time but unfortunately most learners can hardly have such an environment to learn and practice English. That is why we also need more time on reading, listening and writing practice to improve by ourselves.