Here is my advice: Never try to memorize unrelated words. Think about this: what is the use of learning the word "image" instead of learning "create an image", "tarnish the image", etc.? Therefore, you should memorize at least phrases rather than individual words. 

Another piece of advice is that you can create a scenario in your mind when you learn a new expression so that when the scenario actually turns up, your brain will retrieve those expressions automatically.

I think a lot of people do what you are doing, Anderson... but then they don't review what they have written down enough ;)  Revising is the thing that is going to get those words into your brain and eventually into your active vocabulary.   Anyone can write a list of words, but actually using them in a sentence is a different story.  Some suggestions for you...

-Good old fashioned paper flash cards! Get some small note cards and write the word in English on one side and the definiton on the other.  Best to do the definition also in English to get out of the habit of trnaslating from your language.  Add an example sentence as well!  Have a set amount that you review each day and keep adding new words.

-Anki http://ankisrs.net/ You can create your own set of electornic flash cards

-Memrise- http://www.memrise.com/home/ Memrise is an online learning tool with courses created by its community. 

-Write sentences and stories using your words on the list.  Use the words!  http://skypenglish4u.com/memory-retention-remembering-vocabulary-words

I usually keep a small notebook for words in French and Russian. It's faster than the phone or tablet and I can take it everywhere. Then I pass the words to another format. It has helped me a lot! :)

reading is the main tool for increasing it.  But not readind "texts" or "whatsapp" ...real reading:)

OR  you can put post-it everywhere in your house, writing the name of the object you try to learn in that foreign language, but you keep forgetting its name.  A lot of my students use this method and it works!