One thing I've found even better than code review is pair programming. At the recommendation of the tech lead we all did it for the four years at my last job, and it was a fantastic way to spread knowledge around. For thorny prpblems we'd even "mob" on them, four or five of us sitting in front of one big monitor, rotating who used the keyboard and mouse, discussing and giving high-level instructions to the driver. We collectively figured we produced features about as fast as with individuals programming (because of the intensity and avoiding many dead ends) but that the quality was far superior. Reviewing the process honestly (without getting personal) is key, though, to address inefficiencies and interpersonal issues.