I give up I’m terrible at this.
A couple of suggestions. One you are already familiar with. Visit the Robbins Museum and see up close virtually every single class of artifact known from Massachusetts.
The other suggestion is to stop focusing on big rocks and learn to recognize what amounts to 90+% of artifacts that all of us find: flaked stone, in the form of flakes, points, scrapers, etc. The average point will not be a big rock, and large artifacts, like ground stone tools, will never be common finds for most of us. Abraders are not rare per se, just not seeing it here.
That said, your best bet is to learn to recognize the lithic materials used in your region for the production of flaked stone artifacts: quartz, quartzite, argillite, Rhyolite, jasper, flint from the Hudson Valley and imported at times, hornfels, etc. Learn to recognize those lithics and look for them on the shores of our New England estuaries, and in agricultural fields, washed by heavy rains, and with permission. If you can find someone to take you on a hunt, that's really the quickest way to learn, but no substitute for seeing as many flaked artifacts from Ma., and then putting what you learn to work on beaches and in fields. Forget the big rocks for the time being, and concentrate on flaked stone.
Put yourself in the right places to find artifacts, and learn what to recognize as you walk and scan the ground. No reason to give up.
Maybe it's not easy for you to visit the Robbins, but a few hours there would really go a long way. They even have a display of the type of lithics found here.