Hey, Anny. The answer is: Massive amounts of input => Acquisition. Switch all your devices to English. Switch your computer and all your installed software to English. Forget about reading Revista Semana or El Colombiano. Read and listen to the BBC every day. Switch your home page to google.com/ncr (Google in English) and perform ALL your searches in English. Forget about watching movies or series with Spanish subtitles or (God forbid) Spanish dubs. Always watch them in English, with English subs if available. Forget about Cumbia. Only listen to music in English. Delve deeply into complex reading materials in English. Forget about reading poor Spanish translations of scientific reports: Look up the originals. Source: This is exactly how I reached C2 (According to the OOPT I took today, which will soon show up on my profile) The only difference between a native speaker and an ESL learner is the amount of input each one has had.

As Miguel ELE said, massive amounts of input. I will add "writing and then more writing." One of my students recently achieved a C1 level. Briefly, he is a French-speaking lawyer who has a good level of school English. He and his wife moved from a francophone region into a bilingual region where English is dominant. They both work in a francophone environment but are expected to have functional English (about B1-B2) for situations involving anglophones. He and his wife lacked confidence and wanted a higher level of English. For about six months, he and his wife took weekly two-hour conversation lessons with me (about 50 hours). In that time, we fixed assorted grammar, vocabulary, and pronunciation faults. They regularly read English news and magazines that appealed to them. They became fluent for discussions about work and family. Let's call it B2. For the following six months, they continued to take two-hour conversation lessons (another 50 hours) and started reading novels. Importantly, they started writing about a range of topics (childhood memories, difficult situations at work, ...). The writing pushed them to a new level. Now, in speaking and writing, they are indistinguishable from C1 bilinguals who grow up in this region. They have a hint of a francophone accent and occasional vocabulary problems with false cognates.

Hi Anny, as well as the great advice you've already been given above, I would suggest having a strategy/plan and stick to it to practice the four core skills everyday. Getting your writing to a C1 level takes time, although your writing already seems very good from your question above. Learn advanced vocabulary, collocations, phrasal verbs and idioms, lots of reading, listening and speaking about the topics that generally come up at C1 level, and of course taking lessons is an obvious suggestion, particularly for writing as you will need someone to correct your essays and guide you in the right direction. Do some practice tests as often as you can. Hope this helps but let me know if you have any questions. Sinead

Hi Anny! Practice , Practice, Practice. Practice makes perfect. Please navigate and review Cambridge website.