Accedia, an overview of catholic (and other, if I remember correctly) writing about sloth, plus a personal memoir. As I recall, quite an interesting book, but not personally useful-- and this is backed up by the top three amazon reviews.

The fact that such a seriously researched book doesn't turn up much that's easily useful (a more careful or motivated reader might have found something) suggests that there may not be much practical advice in the tradition.

This is reminding me of Theodore Sturgeon's complaint that Christianity told people to be more loving, but didn't say anything about how. (From memory, I don't have a cite.)