You prepare for IELTS during this pandemic the way you would have prepared for it if nothing had happened. The only thing that you perhaps would not be inclined to do right now is visiting an institute and taking coaching classes for IELTS preparation. Well, sometimes it helps not to learn from there. I’m penning down what I think you should do instead. If this helps you somewhat, do drop in a line and let me know here. Will make me feel good :)
Familiarize yourself - God lies in the details. Quickly go through the IDP/British Council websites for the necessary information regarding the test format: number of modules, the various parts into which they are divided, and the time provided to complete them. The more you engage with this exam at every level, the better prepared you will be.
Collect good IELTS materials - especially the Cambridge IELTS series of books (5–14 is ideal). For Academic IELTS, it should provide you with 40 tests. For General Training, you will get 28 tests. These books, along with the Cambridge Official Guide, should be more than enough for the next 5 weeks of preparation.
Take a non-timed Reading/Listening test - use up only one of those 40 tests. Now sit with it and analyze your response, trying to find out why you gave that answer and why it is wrong. I tell this to my students all the time: analysis of your response/s will help you improve your score dramatically. It is imperative you know why you messed up.
Draw up a schedule - 13/14 questions of Reading & 20 questions of Listening. Everyday. This is to be followed from the day after you have taken the initial non-timed test mentioned in 3. The homework is to be renewed every week or so. Download sample Answer Sheets from the internet. Work on them. Familiarity will relax you and provide you that slight - but invaluable - advantage in the exam hall.
Speaking is to be done daily - 20 minutes/day should be more than enough. At the back of every test, you will have a page of Speaking. 40 tests = 40 pages of Speaking questions; Cambridge Official Guide provides 8 more pages of Speaking questions. Apart from this, go to IELTS Preparation: Free Tips, Lessons & English and look up the Speaking section and find the practice questions arranged by section. Avoid ‘learning’ how to speak. Speak like the way we do: concise yet comprehensive; relevant though not abrupt; entertaining while not rambling and going off-track.
Start writing after the first week - this is the most difficult module and preparation time will depend on your current level of proficiency with the language. Go through the sample writings at the back of the Cambridge papers to understand how you should approach them. Write a task 1 piece - take the topic from the writing part of the test you have done - and compare it with the model response provided. Analyze and improve. Also, try to get your writing attempts checked by people who are good in written English (it is slightly different from fluent speakers of the language). Browse the internet for IELTS Writing groups. Joining a couple may help you somewhat.
12-day schedule - this is to be followed only for the last few days before the exam. These will be the timed LRW tests on a daily basis: 40 minutes for Listening (including 10-min. for transferring the answers to your answer sheet), 1 hour for Reading, and 1 hour for Writing (both the tasks).
I hope this is detailed enough. This much you can - and should - do on your own. Practice every day. Remember, a little a day goes a long, long way. Excellence is after all a Habit. Live it.