You must be careful, try to avoid scam projects!

First of all you need to read their white paper. There are lots of information, which can be helpful before invest money into the coin. And Google is your friend  There are videos, articles, sites, researches etc... If you spend enough time to explore the coin, you will get almost an overall picture about it.
And of course this forum is very useful as well, you can get information about the new and popular ones