Here is what worked for me

1. ALGO
   Get a leetcode premium subscription. I had borrowed it from a friend (not under this account), but it's worth the investment. Try to solve problems of different complexities- easy, medium and hard, have a good distribution. Avoid looking at solutions too early. Bang your head on the problem, it might look like you are taking a lot of time at first, but that is what develops your problem solving skills in the long run. Do practise writing code for these questions, just knowing the solution is not enough. Companies expect you to write complete bug free code in time, that too on plain text editors, no IDE features available. Another recommendation would be to pick one language and stick to it. Know all the std library functions in that language like how to sort, hashmap, set, priority Q etc. It won't be fun googling for such things during your actual interview :). I have actually seen people do that and waste precious time.

2. DESIGN
   Prepare for both system design (HLD) and low level design (LLD). You need to read a lot about distributed system concepts out there. There are ample resources on the web for learning system design concepts. I would recommend Gaurav Sen's system design course. Even back when I had applied for another FAANG company, I had watched his system design youtube videos and they were quite helpful. Now he has launched a dedicated course for it. It's worth the investment. You can get it here - https://bit.ly/3DxaFL2

3. PRACTISE PRACTISE PRACTISE
   Solve a lot of algo questions, practise system design end to end - meaning think, write, draw like how you would do in a real interview. Do mock interviews to boost your confidence talking in front of an interviewer. Believe me, people get nervous in front of the interviewer and screw up even in simple questions.

4. TIME YOURSELF
   In real interviews you are time bound (45 mins to 1hr depending on company). Make sure you practise solving questions within that time. Especially system design, where you need to think, explain, write and draw all in 45 mins.

5. APPLY
   You will never feel prepared ENOUGH to apply. It happens with most of us. Set a deadline for your preparations and then just start applying to companies. Apply to multiple companies - it serves two purposes - backup as well as practise. You might want to schedule your dream company somewhere near the end though.