Some of the books which have been of most influence on me are:
David Van Reybrouck (translation by Liz Waters, 2016), Against Elections: The Case for Democracy; Bodley Head.
Josh Lerner (2014) Making Democracy Fun: How Game Design Can Empower Citizens and Transform Politics, The MIT Press.
Josh Lerner (2014) Everyone Counts: Could “Participatory Budgeting” Change Democracy?; Cornell Selects, an imprint of Cornell University Library.
Brett Hennig (2017) The End of Politicians – Time for a Real Democracy; Unbound, London.
With the exception of Making Democracy Fun, these are all available in digital form, ready for instant indulgence.
There is also a recent TEDx talk by Brett Hennig (https://www.newdemocracy.com.au/in-the-media/410-brett-hennig-tedx-talk).