Check it by yourself.
Educate yourself.
Invest.
There are lots of coins these days in the market that are not a scam, but due to the nature of the cryptocurrency market people are still going to think that these coins are scam. These days It is usually hard for you to differentiate between legit coins and the ones that are not legit, unless you’re going to take your time to start looking into the project and what it is all about, and as well check the team that is behind it and know whether they’re truly who they claim to be and their past experiences in handling such projects.
So, it’s just a lot of things to do and it requires a lot of work. Then another thing is that the team behind the coin is also required or expected to play their part by working hard and improving their project and also promoting it on different social media platforms, because that's what is going to tell people that this project is totally legit.