I've found that it's easier for me to focus when I speed up the audiobook's playback sufficiently that I have to exert some small effort to follow what's going on. The Audible app on the iPhone lets you speed up the playback up to 3x. I now listen to all my audiobooks at that maximum speed. As an added advantage, you get through a lot more material.

The cost of this technique is that the extra attention required might preclude you from effectively performing some of the manual tasks listed as benefit (1) in the post. I usually only listen to audiobooks while I'm working out, walking somewhere or using public transport.