A really simple good-enough approach is to go to Google scholar, type in the title, and count how many citations it gets. Adjust for years since publication. Many citations: probably important. Few citations: less important. No citations, more than a year old: probably not much good.

It isn't perfect. Different disciplines tend to cite at different rates; and you may believe that some disciplines are just cabals of bullshitters citing each other. I couldn't possibly comment.