Categorize your cards, and when you come back focus on the categories you want to work on. I think Anki allows tagging. I use Memrise and it allows you to split

Categorize your cards, and when you come back focus on the categories you want to work on. I think Anki allows tagging. I use Memrise and it allows you to split courses into different “chapters”, which all share the same course database. In fact, it allows you to pull in data from all existing public Memrise databases.