For fasting to have the desired effect of disciplining the nafs & weakening its worldly desires, these three adab are needed:

1. Stay awake while you are fasting & actually experience the pangs of hunger/thirst
2. Do not eat excessively during sahur and iftar
3. Do not complain

To clarify point 1: this does not mean one literally stays awake for every min. of the fast. What it means is you do not sleep through the fasting day in a manner where you actually fail to truly experience the fast itself.

Far too many people have a habit of staying up till sahur and then sleeping for the majority of the fasting day. This is an ineffective fast.

The only time this issue gets complicated is in northerly areas where sahur is very early (like in the UK in summer).

Or for people who might have odd working hours, such as night-shifts and the like. But hopefully, the reason for point 1 is clear.