Sometimes I wonder if we've gotten too comfortable with the idea of everything being instantly free. I remember hunting for new stuff to read and hitting paywalls everywhere, which is frustrating, but also made me appreciate libraries more. These days, my first stop is actually the publisher's own website or the author's official site. A lot of them put up the first few chapters as a permanent sample, like Tor.com does for their new sci-fi and fantasy releases.
It feels cleaner than digging through aggregator sites that are packed with intrusive ads. I also check if the ebook is on Amazon's Kindle store because their 'Look Inside' feature usually lets you read a solid chunk. The downside is you need an account, but at least it's a legal peek. For web novels, platforms like Royal Road are built on that model—entire stories free, supported by Patreon for ahead-of-time chapters.
Honestly, the most reliable method I've found is combining a few of these. Start with the official source, then maybe check a major retailer's sample. It saves time and you avoid those sketchy pirate sites that never format right on my phone.