You should just try to go through the right source, if you are making use of an exchange already such as coinbase.com and Binance.com, these exchanges already do announce new coins that are listed on their platforms. So, what you have to do is just to sign up for their newsletter and you will be getting notifications through your email whenever they list any new coins on their platforms. Then you can as well sign up for coinmarketcap newsletter, they do also announce new coins during their airdrops and all that, you can join and also stand a chance of winning those airdrops.

These are the only sources that I’m going to recommend to you, I don’t know any other ones, but you should also try to be careful not to go through the wrong source to avoid fake coins and scam.