If you started your hive on foundation, don't expect too much. If you happen to get it, then bonus!
If you started out on drawn comb, then you might expect a little more.
Nectar flow....short of the methods you mentioned, it is a matter of knowing what is flowing when and how much it is producing. Get to know the trees in the area, correlate that to what you are seeing in the hive and when. The primary producers in my area are the different types of trees, sweet yellow/white clover, and knapweed. Get to know the area and the flowers. I've learned more about plants and trees since bee keeping that I ever knew before. It takes a while to figure all that out.
Rick