In order to be a good writer, you have to read a lot. That goes without saying, and it’s something I’ve stressed on this blog before. If you want to create movies, watch a lot of movies. If you want to be a basketball star, watch some basketball games… etc.
I think that rule goes for critiquing as well. Critiquing others’ work helps you to find the flaws in your own work. If you read plenty of published books, both good and bad, classic fiction and genre fiction, mysteries and romances, you’ll start to see what works and what doesn’t work.
Then, when you critique someone else’s fiction, you’ll know when something seems “off” to you or when something just isn’t working right in the story. You’ll be better equipped to point out flaws. It’s hard to get the right “balance” when you’re writing: is there too much description, or too much dialogue, is the setting too vague? Maybe this writer has great dialogue, but there’s no description and you feel like the characters are talking in a white room. Maybe they have paragraphs and paragraphs of beautifully written description, but no character development. Perhaps they’re trying to write a thriller, but there isn’t enough suspense… etc.
Not all flaws are that obvious, though. Sometimes you’ll find something that you know is wrong, but you’re not able to put your finger on exactly what it is that’s wrong. That happens to me quite often when I’m critiquing my own work, and others’ work. I usually come back to it later and can then figure out why that part didn’t work well for me. Let your subconscious mind work on it for you!
Basically, the more you critique, the better you will get at it. So keep on reading!