For general practical guides I'd look at one or both of:
* "Practices of an Agile Developer" http://amzn.to/9B7hJg, which talks about various practices in a fairly methodology independent way. The reason I really like it is that it has some excellent pointers for checking when adoption is/isn't working.
* "The Art of Agile Development" is another nice book http://amzn.to/bksP7T in a similar vein. This is more process-prescriptive though (they're talking about a varient of Extreme Programming)
I'd also also take the time to read the seminal books on the two most important (in my opinion) agile methods:
* Agile Software Development with Scrum http://amzn.to/bOkPZ1 - the book that formalized Scrum
* Extreme Programming Explained: Embrace Change - the book that formalized XP. Read both the first http://amzn.to/cdLAtx and second http://amzn.to/bqMhEa editions if you get a chance. They're interestingly different.
I'd also add the various books on Lean by Mary & Tom Poppendieck http://amzn.to/9wsASi and also 'Kanban' by David J Anderson to the list http://amzn.to/en6PQ2 as well.
You might also find these of interest:
* The Scrum Guide - http://www.scrum.org/Scrum-Guides
* The Agile Atlas - http://agileatlas.org/
* The Agile Alliance's Guide to Agile Practices - http://guide.agilealliance.org/
lots of useful info there ;-)
1. "Extreme Programming Explained" explains the importance of separating values from principles and practices.
2. "When Agile Gets Physical" unpacks why using agile software best practices are horrible for hardware. This is "duh" if you're a hardware person, but the book goes back to agile/lean first principles, and then builds up an approach for agile hardware.
It got me thinking that we often conflate values and practices. Blinding adopting Scrum or DevOps without understanding some of the underlying value and principles leads to problems. If you understand the foundational principles, you're in a much better position to adopt/reject certain practices for your given situation.
In reality, most organizations just adopt a few agile practices, while rejecting the basic values.
[1] https://rapidlearningcycles.com/when-agile-gets-physical/
[2] https://www.amazon.com/Extreme-Programming-Explained-Embrace...