You could read magazines online, they would have articles with commonly used language in. If you're interested in fashion there are magazines like Elle, Cosmopolitan, InStyle, Vogue, Nylon. The Guardian is an online newspaper, I don't know if it's available outside of the UK. Young Adult fiction would be good for commonly used words. If you google 'the 100 best young adult fiction books of all time' you will get a good list. I'm sure there are lots of other ways, but I hope these ideas help!

This is what I recommend for my students: Copy an article from the Internet to a word document by cutting and pasting it. Ensure this article is relevant to the topic you wish to increase your vocabulary in. Save the document. Read the document twice without trying to understand the words or phrases you are not familiar with. Read through the document again and change the colour of every word or phrase you do not understand to RED. Read through the document a fourth time, this time looking up definitions for what is in RED in the dictionary or on google. Type in these definitions after the word or phrase you are unfamiliar with, in BRACKETS, in RED, and in ENGLISH (do NOT translate them to your native language). If you still do not understand words or phrases change their colour to GREEN. Ask a native speaker/teacher to help you with the GREEN words and phrases. This will increase your vocabulary and understanding.

This is what I recommend for my students: Copy an article from the Internet to a word document by cutting and pasting it. Ensure this article is relevant to the topic you wish to increase your vocabulary in. Save the document. Read the document twice without trying to understand the words or phrases you are not familiar with. Read through the document again and change the colour of every word or phrase you do not understand to RED. Read through the document a fourth time, this time looking up definitions for what is in RED in the dictionary or on google. Type in these definitions after the word or phrase you are unfamiliar with, in BRACKETS, in RED, and in ENGLISH (do NOT translate them to your native language). If you still do not understand words or phrases change their colour to GREEN. Ask a native speaker/teacher to help you with the GREEN words and phrases. This will increase your vocabulary and understanding.

Although I'm not a native English-speaker, I would suggest to use a frequency dictionary. It's a dictionary where the most frequent words are located at the beginning while rare words are closer to the end. You may move forward in understanding English texts and expressing your ideas much faster, if you learn the most usable words first. See http://www.savingthewahyanites.net/wp-content/uploads/2012/01/Hirsh-Nation-1992-WhatVocabularySizeIsNeededToReadUnsimplifiedTextsForPleasure.pdf There you may find an example of a frequency dictionary : https://www.wordfrequency.info/files/entries.pdf

Don't you think that people who learn English may know such things better that native english-speakers, unless the latter have a significant experience in learning foreign languages?