This was my second interview for an SDE position with Amazon.

Biggest tips:

• Relax
  • They're interviewing you, at this point they're fairly certain they could hire you. A big part of what they're looking for at this point is who you are as a person, your manerisms, your communication skills, and, of course, if you can actually write code

• Be confident in your answers
  • They want to see how YOU approach problems, not a regurgitation of how the top-voted answer on Stack Overflow would approach the problem

• Be prepared to defend design decisions (with actual data)
  • They might ask questions while you're writing code that can sound like a leading question into solving the problem a different way - That does not mean that they're telling you how to most correctly answer the problem. It's a discussion. If you think your approach is better, state why you think your way is better. There's a good chance you're being challenged just to see how you back up your decisions.
  • Every decision at Amazon is a data-driven decision. You can't defend your approach with an emotional or half-baked response. Weigh the options, discuss pros and cons of each, analyze memory consumption and runtime.
  • "Because that's how I know how to do it" is NEVER a good answer. If you don't understand the suggestion, ask questions.

• ASK QUESTIONS
  • The interview is more of a discussion and a trial of how you operate with team members. If you don't fully understand anything, ask for clarification.
  • It's better to admit to not understanding to gathering useful information to lead decisions than to just charge headfirst into what your first instinct tells you is the best answer.
  • At the end of each interview session, there's time set aside to ask questions of your own. Have questions ready. Real questions about the work environment and position shows that you are interested in applying for THAT position, not just applying for ANOTHER position.

Excited to join the AWS team.
Good luck and happy hunting.