The year was 1999. I never knew personal computers and the Internet had already existed. I bought myself a notebook with a minimalist design and began writing down useful expressions.
However, I never rushed collecting keywords. What I did was like sipping a hot 3-in-1 organic coffee while watching TV. I was doing it nice and slow. I would read. I would write. I would recall.
There's something I would like to tell you that you probably already know. No amount of memorizing can help you remember words. Today, you can find a huge list of keywords and key expressions on the Internet for free.
Great job and thank you. But memorizing them is a temporary and unrealistic solution to your permanent problem. You attempt to remember them now; you forget them later.
I have personally witnessed Korean students being forced to wake up at 6 o'clock every morning almost every day to memorize 50-100 words. I knew one student who went back to his home country not remembering a single term.
When I met him again on Facebook and asked him how many words he had learned, he refused to even think about this whole experience. Taking too much data all at once is a bad idea.
Here's my idea: Read, then write. Read a bunch of books and blogs. If you like watching TV series and movies better than reading, then watch them with English subtitles.
Listening becomes hard work if you have less input. Your ESL mind isn't that developed yet. With too much thinking going on, your clouded brain can't handle watching and listening at the same time. Your brain will look like a windows program not responding.
That's why you complain, "They talk so fast!" Subtitles reassure you read, follow, and understand what is being said.
Be it reading novels or watching films or listening to music, watch out for phrases that spark you. Write them down. I myself have been doing this until today. I do keep a notebook and bring it with me most of the time.
You never know when the next finest of all expressions is going to show up. So, I seek out every opportunity to capture them even on occasions I least expect them to come out.
While watching movies, I keep a close eye and ear for interesting dialogues. These are expressions I could sense I have somehow spoken before—only that they were spoken in my own language.
Your goal, therefore, is to associate a newly-discovered English expression you've found somewhere with your personal experience until it becomes an inseparable part of you. You might ask, "How is it exactly done?"