In smoking cessation classes, they emphasize small victories - "that's one cigarette I didn't smoke!" Try taking that approach - maybe go lower nic ("only 12 mg today!") or less juice ("I only went through 1 ml today!"). Sounds cheesy, but those little reinforcing thoughts do help. I have a nano clearo miser that holds about 1 ml - I use the visual indication to keep me less than one ml per day.