Zero diopter reset
When introducing a reduction, it is not advised to just slap them on your face, as the visual cortex associate the change with lowered clarity, which is bad. You want to start with lower correction before introducing the reduction, which makes the visual cortex associate it with increased clarity.
Do: be sure to wait the recommended time frame (4-6 weeks minimum) between correction changes. And as a rule stagger your reductions. For instance your first ever reduction should be Differentials then after 4-6 weeks to adjust to those corrections as well as introduce and solidify good habits you can bring on the Normalized correction.
Do: be sure your new reduction is actually justified by measurement trends in your vision.
Normalized
As a rule, you never want to wear your new lower normalized on the same day after wearing your full correction or previous normalized correction.
What you do is take a day you can manage with no correction (or differentials in the case of high myopia) from the beginning of the day for as long as reasonably possible, until you start to feel uncomfortable. This way when you introduce your new normalized the relative standard for expected clarity is that things are much clearer and this is a good change. The good association with your new correction is a big advantage.
Make sure to wait for the right day. There is no good reason to rush a reduction, waiting an extra day or more will not do harm, in fact a little time to lock in your current gainz is a good idea.
Keep the previous normalized (or full correction) handy for night driving.
Differentials
If you already wore the previous differentials, do not wear the new differentials until the next day. Once again no need to rush a reduction.
Low Myopia
Instead of reducing from -1.5, -1.25, or -1 (based on personal preference), the current EM strategy is to alternate zero and normalized correction, which is called "Low Myopia Zero Diopter Reset Trick".[1]