Besides all the good ideas suggested by others for high-level process optimization (small PRs, self-review first, prioritize reviews, have a larger pool of revi

Besides all the good ideas suggested by others for high-level process optimization (small PRs, self-review first, prioritize reviews, have a larger pool of reviewers, etc.), you can also micro-optimize the time spent on reviews proper. A good tool can help a lot here: it will show incremental changes since the last review round (even if the branch got rebased), filter out changes due solely to rebasing, track resolution of any issues raised during the review, etc. If you're using GitHub, the built-in pull request review system doesn't really do these things very well (or at all), so you end up wasting a lot of time and/or missing things. There are a number of third-party options that do much better but some of the best require you to host your own infrastructure, move your repo, etc. Selfishly (and again, only if you're using GitHub), I'd recommend checking out https://reviewable.io https://reviewable.io, as it integrates smoothly and requires nearly no setup. (Disclosure: I'm the founder.)