RPGMemes

You can't. You can do better sometimes but there will still be hiccups. As far as I'm aware the groups most likely to be actually consistent have been playing together since they were in school.

This isn't meant to be discouraging at all! The opposite in fact. Don't let those hiccups, common or rare, stop you. Just be aware of their possibility and ready to adapt. Ability to adapt is the most useful tool in the GM toolbox at the table and approaching it.