I have been there.

Not once, not twice, but 6 times this past year. (Once at Amazon, thrice at Microsoft, once at Expedia and once at Apple).

And I got a reject. All 6 times.

In December I attended an Amazon interview again, and I have a job offer from them now.

How did I turn it around? What was the magic sauce?

Of course, you’ve to be strong in your fundamentals - Data Structures and Algorithms, but there are few other things you need to focus on (I’ll keep my answer specific to Amazon) :

System Design - Most people tend to focus a lot on programming questions and think they can answer System Design questions on the fly, with little or no preparation. This is a mistake as System Design questions truly expose your knowledge of software systems and how they work at scale. Make sure you gather requirements and ask qualifying questions before you start with your design, as these questions have no one right answer, and what you ask tells a lot about how you think. Your ability to articulate and devise a system based on the requirements will go a long way in not only getting an offer but in determining your level when you join the company.

Behavioral questions - All Amazon interviewers spend a good chunk of the interview on behavioral questions. Questions are usually of the kind “Tell me about a time when…”. These questions explore how you handle the various challenges you face at work, be it technical or interpersonal. A good way to prepare for these questions is to have a short summary of a situation you’ve been in the past in STAR (Situation, Task, Action, Result) format for each of the 14 leadership principles of Amazon. Even if the questions you are asked aren’t strictly from these principles, you can still use the same situations to tell your story.

Coding - Most interviews will have 1 or 2 coding questions. My approach to these questions was to talk about a brute force solution first and then code an optimal approach later. Try to make your code clean and abstract wherever necessary. Interviewers love to see clarity in code. After writing the solution, walk through a few test cases of your own to see if it works as expected. Make sure your test cases are varied enough to consider all edge cases (negative numbers, Integer.MAX_VALUE etc.). Tell them if you know of other approaches for solving the same question. Learn how to determine running times for different types of questions, especially dynamic programming and recursive approaches.

Project confidence - Interviews are tough, and there will be questions which you haven’t encountered before, or sometimes don’t know how to begin with. Try not to panic in this situation, and most importantly think about how you will approach the problem before talking out loud about it. Sometimes interviewers will tell you if you’re on the right track and you can proceed from there. Think about what data structures would work best for a scenario. Most of all, project confidence and believe you can find a way to solve the problem.

Ask questions - Interviews are not only about the company evaluating you but also you evaluating the company. Having this perspective will give you confidence and not keep you on the backfoot. Ask the interviewers about the role, the technology stack, the challenges they’re trying to solve, work-life balance etc.

Keep practicing - In the end, practice makes perfect. There are a variety of resources to help you in cracking software engineering interviews. A few of them which I used were - LeetCode - The World's Leading Online Programming Learning Platform, Interactive Courses for Software Developers, and GeeksforGeeks | A computer science portal for geeks.

All the best!

P.S - I wrote this same answer anonymously on Quora - https://www.quora.com/How-do-I-pass-an-Amazon-interview-It-seems-that-despite-answering-all-questions-in-the-interview-one-will-still-get-rejected/answers/113642195 . Posting it here so that you don't flag me as plagiarising. I own the edit link to edit this anonymous answer, if need be to prove I wrote it. Thanks!