In my experience, code reviews don't happen spontaneously. They only happen when we carve out time in our workflow to make sure they happen.
Most software development environments are deadline-driven which means "non-development" activities like code review are the first thing to go in a crunch time. If you want code reviews to happen, you have to set aside time and make that time sacred. It can't be forgotten or deprioritized. It as to be seen as necessary as writing code the first time.
10 lines of code = 10 issues.— I Am Devloper (@iamdevloper) November 5, 2013
500 lines of code = "looks fine."
I do biweekly one-on-one code reviews with my direct reports. Its proven to be an incredibly valuable tool. Its a time that I get to see how their skills are progressing and to correct issues. They deepen their understanding of their own code through the process of explaining it to another person.
I also get to present my code for their review. Though I might be a stronger developer in certain areas, everyone's opinions and unique expertise is valuable. Every time I walk through my code with someone else I learn something new, understand something deeper, and strengthen my team