My difficulties in English

I'm Vivian and I'm from Brazil, so my native language is Portuguese (not Spanish lol). I'm studying English, Italian and Ffrench actually and I want to start Spanish and German studies at soon. Always by myself.

For a long time I don't write anything in English (without a theme ?), so I can be "rusty". I have some difficulties in English, especially with pronunciation of some words, because I was "tongue-tied" when I was a child.
Another difficulties are when I use vocabulary. I always think about the things such are : What word is better? Kid or child?  Is there a better solution than those ones ?
I haven't nobody to practice with, to make conversation, etc. Actually I met a lot of people for talking in French, but anyone to talk in English - It is interesting and strange.
I want to improve my vocabulary, but I have not found yet an effective way to make it - The teachers used to  say "study 10 / 20 words" for a day. But how can I make one list of words?

I'm studying a lot: I'm making an online course supported by the government, I use books, I'm making regular classes at a school and making a thematic course at uni too (for business, travelling, etc), I read books in English and listen to music too, but I'm not feeling a gradual improvement in order  to be fluent. When I talk (or write) in English, I think in English, I don't a translate of my thoughts but I don't feel safe with my English yet.

How are you studying English? How did you became fluent?

Thanks,
Viv.

Viv, I am not a native speaker of English, and my corrections of your text could be poor. Hope I did my best. If you need some more explenations, please contact me.

Kamenko

** I don't found an effective way to make it - teachers say "study 10 / 20 words" for day. But how can I make a list of words? 

**I don't make a translation of my thoughts but I don't feel safe with my english yet.