My biggest and dumbest mistake cost me a fish.
I had a pair of clowns in quarantine and one had visible signs of ich. Our QT is a 20 gallon tank but we didn't fill it full - only used 15 gallons. So...time to treat for ich. I dose for 20 gallons. I realize it right away but just leave it. Do a water change the next day before a second treatment. Instead of measuring, I do drips - a different way to measure and outlined in the instructions. The ACTUAL instructions is ten drops per gallon, but for some reason my head converted that to one drop per gallon. I kept dosing and doing water changes as I watched the one clown get worse. I finally realized what was going on and started dosing correctly but it was too late.
Lesson learned and I read dosing directions almost EVERY time I dose anything.
