It's really hard to tell whether an ICO will scam you or not but there are some certain measures that you should be doing before investing in an ICO. For you to be able to know about the project you should read the whitepaper for you to understand the nature of the project whether it is realistic or not. It is also very important to know the people behind working with the project. You need to research as well of the possible affiliates that this project have to back them up for their development. Make sure that the project will also address a certain problem that most tokens or coins wasn't able to deliver for it to be useful and have value when its launched to the public and always follow your gut feeling and intuition almost all of the time it's correct when your in doubt about investing into a scammy project.