Full body pictures once a month are a great way to measure progress. (In my opinion it is the best way)
As to not being able to see changes when you lose weight that is not surprising because you're looking at yourself daily you don't notice the small changes as they're happening. This is where pictures help immensely.
"Getting solid information is easier than ever. Getting misinformation is even easier." - Kaplods
Maintaining for two years and I eat whatever I want - just not however much I want. Details here.