read the reviews from users
Amazon reviews are useful if you use them properly. Click on the ‘verified purchase’ filter. Some of the Vine and other solicited reviews can be excellent of course, but ‘normal’ users give a better overall sense imo. The 4-star and 2-star reviews are often the most informative–too many possible fanboys and shills/trolls in the 5 and 1 brackets.
You should also sort by 'Most Recent' to see if a product has improved or deteriorated since its release. Check the 'shape' of the ratings chart—ideally it'll taper down from 5-star [most] to 1-star [least]. Watch out for 1-star being more than usual, that may mean a product which is good when works but too often is DOA.
If there's some aspect which interests you, look for the nearest match in the keywords in the 'Read reviews that mention' section.
Look for 'Top Contributor: …' beside reviewer's name.
Dishonest review campaigns—ie paid-for 5-star "reviews"—usually last only a short while, so keep an eye on review dates. Such reviews are also almost always easily identifiable as scripts from a marketing person—there must be a special module in marketing school for 'How to write unlike a real person'