I use this technique in 2 ways.
The first way simply uses the camera zoomed in as a live view mode, just like a microscope. My camera has an 8x digital zoom which turns this thin 7mm woven strip into a detailed 37mm closeup. This mode does drain your battery and you will need to have the display setting changed if you normally use a battery saver mode, as the battery saver mode turns the screen off after a designated time period. The trick with this technique is to position the lens of the camera so you can comfortably see your work on the phone screen and have enough room underneath the camera to move your hands, and your work, freely. This can take a bit of time to get right but being able to see wires and stones in so much detail saves a lot of time in finishing a project. You may need to experiment with a range of stands to find what works best with your making processes. This tool enables you to pinpoint problems quickly, it makes learning new techniques much easier by letting you see exactly what is happening and it also gives you the opportunity to have a more professional finish on all of your jewelry.
You can also use your phone handheld as a loupe allowing you to check beads and gems and to see if your solder has flowed in all of the right places.