You may have read a lot of writers making anime and video game reviews. There are also individuals who also devote their time to read through a lot of chapters to share their views about manga series. Like any other review or opinion about these related mediums, there are assets to the subculture because they help fans decide whether to try reading this certain manga or not.
Everyone can make a manga review—it doesn’t matter if you’re not a professional otaku journalist or if you do not have previous experience writing reviews. You just need to remember to keep your opinions balanced. The reason why some people criticize other critics is because they are always one-sided when they review certain mangas. Just because you’re devoted to a certain genre, doesn’t mean that you have to eventually close your doors on the other ones.
This is a challenge to any person who decides to venture into making manga reviews. Be open-minded and do not spill in your first impressions if you haven’t really finished everything (even if the manga doesn’t seem to have any development, bears a cliché storyline, etc.). Who knows, your first impressions about it could be wrong and you would just take back what you say about it.
If you having a hard time writing about a manga, you can seek inspiration from other critics and writers. They can be otakus like you or professionals who have honed their writing skills in this certain category of interest (you’d be surprised!). It’s not like you are imitating their style of reviewing a certain manga; it’s just to give you an idea on what you must do to make your review unbiased and professional-sounding.
Remember this: though you have the freedom to say what you think about a manga, remember that a lot of readers might turn to your review as a guide to help them in choosing the manga that they should read next. Keep it clean, keep it balanced, and be fair. Good luck!