It'll take some investment but I'd start by finding someone else that needs a code review and offer it to them first. From there you mention that you'd appreciate if they scratch your back as well.<p>You can probably find some open source projects where you can offer code reviews to other.
Not sure if this is helpful, but I asked family for code reviews for my birthday. (Requires that you know coders.) This might be helpful: <a href="https://www.reddit.com/r/codereview/" rel="nofollow">https://www.reddit.com/r/codereview/</a>
I personally practice code review on my own stuff - even just me, I'd go through and pick it apart as if it were another person's code.<p>In some cases I have colleagues / friends who'd be able to help out too