For me it‘s a shitcoin if there is no real develoment, no history in achieving milestones that were outlined in the original whitepaper, and unfortunately that accounts for the large majority of altcoins. Then you have copycat projects, that do not come forward with a unique idea but that took the concept from another project. These I would not call shitcoins, but I would still stay away from them as in my experience most are just money grabs too. I am sure there are many other factors, but for me these count the most and serve as a simple compass.