Just look at the project itself the whitepaper, the team and its purpose you will know if the project prospers or not. You will spot immediately if the ico or ieo is a good project if the team is composed of the one well know devs and if the project was advertised by well known cyber techs on this platform and if the DT of this forum is supporting of thaf said project
Not an assured thing and also its not right for you to rely with that DT feedbacks because not all would really be precisely able to detect which is scam or not.
You cant spot out scams even just reading up a WP. or seeing its team because even scam ones nowadays are too really hard to be identified if you dont make in depth research everytime.