This is kind of an extension of the Measure Your Progress tips.
Here’s my humble advice: Don’t rely on just one thing to gauge your progress. Here’s what I use: the scale, pictures, and measurements.
Scales: The scale is usually handy and it’s culturally thrust at us everywhere we turn. But the scale lies sometimes. The scale (especially the ones that purport to measure bodyfat) does about as good of a job measuring fat loss as Steve Buscemi does modeling bikinis. When I do use the scale as a metric, I weigh at the same time of the day. Personally, I like to do it right when I wake up, after my morning ablutions, before I suck down 16 ounces (that’s a whole lb right there, people!) of java.
Pictures: I hate selfies, but will take them on a weekly or montly basis to compare with my before pics. Keep in mind that photos can lie as well. Try to keep the lighting, clothes, and angles consistent. Unless, of course, you accidentally find an angle that takes you from a hard “2” to a solid “10.” If that happens, make it your head shot and send me a cut of your modeling proceeds. MyFitnessPal’s app has a nice side-by-side function that I use to compare pics.
Tape measurements: I think this is one of the most underused metrics, and if I had a nickel for every time someone was worried about the scale stopping, but had no idea if their measurements were still declining, I’d have… wait, lemme see … carry the zero…divide by pi… I’d have about 35 cents. I’m a fan of tape measures like this one. Easy to use one handed and places a consistent amount of pull on the tape. I like to place it and snap a photo for two reasons. 1) I can then add the data to MFP later, and 2) it shows me where I placed the tape so I can more closely replicate it next time. But be forewarned, do not enable auto upload of your pics to the cloud, lest ye be showing your gramma some vaction pics and she ends up seeing your (cough) tanlines.
tl;dr Keep track of more than one thing. I like three things. Not every day, but with consistency.