A decent 30X to 50X microscope works. A decent jeweler's loupe works, too, if your eyesight is pretty good. The cheap made in China ones, like what you might find at a flea market coin dealer's booth can work, but the ones I've seen have a very narrow field of view (or whatever it's called when only a spot the size of a pinhead in the middle of the lens is actually in focus). Pocket 'scopes of various types can work, and some of them are of relatively good quality (and have a light). Using a handheld device to magnify and examine part of a plant that you're holding with your other hand can be a RPITA, lol. The slightest movement of either hand, the device, or the plant - and the thing you were looking at is no longer in view.
Make sure you're looking at the heads of the trichomes that are on the flowers, not the leaves. If your light source is separate, try moving it around, to be sure that it infant influencing your perception of the color/state of the heads. Clear = immature, milky/cloudy = maximum potency, amber = degraded and past peak potency.