I recently started a new job at Uber, and there are many useful tips that can help you get a job in a big tech company.
System Design: Educative recently published an article that covers the System Design fundamentals.
Algorithms and Dynamic Programming: This video from freeCodeCamp, even lengthy, is a great starting point.
Behavioral interviews: Remember some situations when you helped your team in resolving issues, dealing with conflicts, or mentoring other software engineers. To learn the best way to answer the questions, watch the youtube channel Self-Made Millennial.