You must have lots of friends in this forum or telegram group and see new projects on social media.
After that look at the project and how they run the project according to the roadmap, once it's done, look at MC, there you can buy altcoins at low prices when the market cap is under $100k usd, but still do your research before investing, recently I found a L1 blockchain project like Berylbit, the team is still developing the blockchain and you can see it here
https://github.com/BerylBit/Chain-source-