Recommended identification tools
There are several tool that could be helpful during the identification of a species. It is definitely possible to identify with the naked (trained) eye, but tool will make it a lot easier.
Good quality loupe
I personally use a dual lens loupe with built-in LED lights. The big lens is a 30x and the small lens is a 60x magnification. The 30x is the main lens, because it gives a wider field and you're able to see the full leaf or area. The 60x lens is situational and really helps with the fine details of glands or hairs.
Tweezers are my go-to tools, because it's much easier to hold a leaf in place with tweezers than with your fingers. I use 2 types, flat tweezers and pointy tweezers. The flat type are nice, because they're less likely to damage leaves and you get more grip on the subject. The pointy tweezers are handy for detailed work, like picking off anthers for examination.
Camera with macro setup
An optional, but for me personally a very helpful tool is my camera with a reverse ring. This way I can take a picture and get a very detailed look at the subject, and look as long or often as I feel like looking. Your eyes can get tired easily when using a loupe, so having a picture is a nice work-around.