Most coins will have a subreddit where development news is posted.
You could also take a look at the following subs:
https://www.reddit.com/r/BitcoinMarkets/https://www.reddit.com/r/CryptoCurrency/Which have news about trading, markets, scams etc.
Also, Google is your friend. Type in the name of the coin you are looking at + scam into google and see what comes up. When people are unhappy they write about it with scam in the title. Read all the complaints. Sometimes it's down to teh user, but often it's down to teh developers. And of course ask questions about stuff you arn't sure about