I remember staring at the pregnancy tests trying to figure out whether I could see a faint line. Then I googled it and learned about the “evap line”that develops when the urine on the test area begins to dry, leaving a faint, colorless line.
And later I found this gem of a website Countdown to Pregnancy where women share photos of their pregnancy tests and other women vote on whether they think it is +/-. Just looking at the photos was helpful for knowing what to expect (or hope for!).
Source: Countdown to Pregnancy