Comment by WinH

From my experience, you have to have a culture of code reviews to implement code reviews - if that makes sense. I have worked with a number of different teams, and have found the most success in bending the code review process to match the culture of the team. Sometimes that means all code reviews go through a single person, and other times, it means have well documented processes and bi-weekly in-person review (e.g. lots of structure).