An evening with a little room to linger.
Make the first round generous.
The first time through a game is partly an introduction. Keep the reference material within reach and invite people to say what they are trying to achieve. A shared understanding is more useful than a fast result.
Notice the small decisions.
In Reedwater, ask why a certain bend looked promising. In Canopy Routes, compare the paths that nearly connected. Those conversations give a second round its appeal: the table has something specific it wants to try differently.
Put the next invitation in the box.
Sort the cards and pieces before putting the game away. A box that opens neatly makes the next evening easier to begin. You do not need a special occasion, only a clear patch of table and people willing to linger.