I second the recommendation for Waking Up. I previously tried Headspace and Calm, but Waking Up was the only one that stuck for me. I think the difference was the structured nature of the introductory course, good intuitive explanations from Sam Harris and the accompanying "theory" discussions and talks.
That's a good point! I've been reading up on various books Sam and other 'meditators' cite, and he does seem to have a nice approach where he takes 'the best' from various schools of thought and meditation, across Japanese Zazen and Indian Buddhist meditation.
