I have learned to avoid items that look extremely different in every product photo. Sometimes customer service can fix a bad experience, but not always. I like when a shop clearly shows PD, lens height and bridge width in millimeters. Over the last months I noticed that some of my favorite items are not the most expensive ones. For example, I compared cotton, polyester and mixed fabrics for similar clothing items. Sometimes I experiment with different materials just to see how they feel in daily life.
Trendy pieces are fun, but I only buy them when the price is reasonable. At least here we can see more honest opinions and not only polished marketing content. Bad lenses can cause eye strain, reflections and headache when you wear them for hours. I think it is better to build a small collection of reliable products than to buy random cheap things. Online shopping will always have a bit of risk, but experience makes it easier.