1. To have a hangover: This is the most common meaning of "faire lendemain" and translates directly to "to have a hangover." For example:
* "J'ai un peu fait lendemain après la fête d'hier soir." (I have a bit of a hangover from last night's party.)
2. To be sluggish or slow the next day: This meaning is related to the hangover sense, but can be used more broadly to describe feeling tired or unproductive the day after a long or tiring event.
* "Je me suis couché tard hier, donc je fais un peu lendemain aujourd'hui." (I went to bed late yesterday, so I'm a bit sluggish today.)
3. To make the most of the following day: This meaning is less common but can be used to express the idea of enjoying or benefitting from the following day.
* "La journée a été longue, mais je vais faire lendemain en me reposant." (The day was long, but I'm going to make the most of tomorrow by relaxing.)
The best translation will depend on the specific context and the nuance you want to convey.