All right, Luisa. There are good extensions for Google Chrome to help me finding the meaning of the words. I try to stay away from Google Translator, as it works as a crutch. I prefer using a dictionary that provides me definitions in English. This makes me understand the context of the word. The best part is that such extensions can be assigned to a keyboard hotkey, which makes the process of defining the meaning of the words come in handy. So, it's fun to visit websites in English, and whenever you come across an unknown word, you just select it, press the hotkey and voilà. :)

Hello Igor, I'm going to recommend you the things that have worked for me. Read aloud, but different types of reading. It will increase your vocabulary, at the same time, you will practice and improving your speaking (pronunciation and fluency at reading). After you read an article, new, whatever; make a list with the words that you consider most important. And finally, make up statements. While you create a statement you memorize the word and the meaning because you are thinking in the right situation that you can use it. Oh! Another important thing... post your statements here in the notebook section in order to get corrections or suggestions. It has worked for me, maybe it can work for you as well. Don't feel frustrated. It's normal after all. It depends on everyone how to overcome that (try and try different ways) and how fast.

Thank you for your advice. I'll try to use 3 new words in my speaking or writing daily.

First of all, your written english is great. I understood everything no problem. Why not pick 2 or 3 words and make your goal to use those words correctly in a conversation. If someone gives you a weird look, ask if you used them correctly. That way you get some practice. Make them small, achievable goals.