Self Study - General English
My advice is to choose activites you enjoy doing in your own language and then do them in English. For example, if your hobby is ccoking, you could subscribe to a magazine in English, watch videos, buy recipe books in English etc.
Practise every day if you can, even if it’s only 10 minutes. Regular short sessions each day are far more effective than one long session from time to time.
Some useful sites to get started are listed below.
Gymglish

Ce site est payant mais vous pouvez l’essayer gratuitement pendant 30 jours.
Il offre des cours de grande qualité qui vous permettent de pratiquer les 4 compétences.
C’est un cours interactif très original et amusant basé sur l’idée que la pratique quotidienne est la meilleure façon d’apprendre une langue. Chaque leçon dure 10 ou 15 minutes, ce qui est idéal pour ceux qui n’ont pas beaucoup de temps et qui ont besoin de d’améliorer leur anglais.
Coursera

Cette plateforme vous permet de suivre des cours donnés dans différentes universités du monde entier. Il y a une grande variété de cours qui durent plus ou moins 6 semaines.
La majorité des cours sont disponibles en vidéo (avec sous-titres en anglais). C’est donc une excellente manière d’affiner vos capacités d’écoute et de d’enrichir votre vocabulaire.
Vous pourrez faire deux pierres d’un coup: étudier un thème qui vous intéresse et améliorer votre anglais.
Livres
Lire en anglais vous aide beaucoup à enrichir votre vocabulaire. La règle d’or: lire la même chose que ce que vous lirez dans votre propre langue. Si vous n’aimez pas la fiction vous pouvez lire des autobiographies ou des magazines spécialisés sur vos sujets de prédilection.
Et si vous préférez la fiction, c’est une réserve sans limites. Les romans et les pièces de théâtre sont très riches en vocabulaire et une excellente manière d’améliorer votre anglais.
À continuation, vous trouverez une petite liste de suggestions:
Animal Farm – George Orwell

When the downtrodden animals of Manor Farm overthrow their master Mr Jones and take over the farm themselves, they imagine it is the beginning of a life of freedom and equality. But gradually a cunning, ruthless élite among them, masterminded by the pigs Napoleon and Snowball, starts to take control. Soon the other animals discover that they are not all as equal as they thought, and find themselves hopelessly ensnared as one form of tyranny is replaced with another..
Other ways to practise
Watching TV series and films in English with English subtitles is probably the most powerful self study tool available. Apart from Netflix, HBO, Disney, Apple TV etc, you can also watch British TV by using a VPN.
When watching, I recommend you alternate between active and passive sessions.
Passive sessions involve watching a show without stopping just for enjoyment. Active sessions are when you stop the video and note down new vocabulary and a translation into your own language. If you write new words in the context of a sentence. you'll remember it more easily. When you re-read the words even months later, you'll often remember the exact scene it came from.
Practise watching shows in Enlgish without subtitles too from time to time without stopping the video. This can be frustrating at first but by removing the crutch of subtitles, you force your brain to process the information differently and will greatly improve your ability to understand gist.
Whatever you enjoy doing in your own language you’ll enjoy doing in English as well.
You can learn an enormous amount by yourself, partcularly with regards to listening and reading comprehension.
OET Self Study
Apart from numerous activities which you can find on the official OET website, I recommend the following.
Zero to Finals
This is a great site for refreshing your medical knowledge and learning English vocabulary at the same time.
Health Check
This BBC podcast is excellent for practising your listening skills on a wide variety of health related issues.
The Guardian - Medicine
A good way to build vocabulary and improve your reading skills is to read articles related to medicine in newspapers such as the Guardian. You will find a good mix of medical and lay terminology.
IELTS
Fastrack IELTS
One of the best free sites is Fastrack IELTS presented by Asiya. Her videos deal with all parts of the IELTS exam and are focused on how to maximise your score. Easy to follow and excellent practical advice on how to approach each part of the tes