I highly recommend "Don't Think of an Elephant!" to anyone interested in progressive politics. The book is very well written, easy to read, concise, and important.
The basic premise is that, over the last few decades, republicans have gotten good at framing issues in terms that implicitly support their worldview. Democrats have used the republican framings and language even when trying to argue for progressive policies, but using the republican framing has the neurological effect of reinforcing the republican framing.
Lakoff provides plenty of examples of political issues along with successful and unsuccessful ways of framing those issues. He also discusses the values underlying progressive politics as well as conservative politics and talks about how to build coalitions around those values and how to talk about those values.
One interesting argument in the book is that the idea of moderates is a myth. There are people who mostly have progressive values, people who mostly have conservative values, and people who have some of both. To be clear, though, "some of both" doesn't mean that they have a coherent political philosophy. Rather, it means that the philosophy underpinning half of their beliefs might contradict the philosophy underpinning the other half of their beliefs. Lakoff calls this group "biconceptuals" because they have two mental models at the same time. Political campaigns often revolve around these biconceptuals because people who have a strong or consistent set of beliefs have probably already made up their minds.
If you are involved in politics or are just generally interested, you should read this book.