You must look for the coins potential if it will be able to sustain its needs for a long time. Also check the backgrouns of the developers if they have been part of some successful project for you to check if they are legit or scam. Also check the current market movement if the value of it is good to invest to or not.
Also consider the current trend of the market, do not go for Altcoins make your investments with Bitcoin because it is more stable and trustworthy in crypto market. Before investing have a full command over the knowledge of market, its working and the most adopted strategies. Choose the way that best suits you, you can also take guide from other successful investors.