In keeping with the angel sign theme. I would like to suggest the book "Signs from above: Angelic messages to guide your life choices"
by doreen virtue. Here is the link Amazon.com: Signs From Above: Your Angels' Messages about Your Life Purpose, Relationships, Health, and More (9781401918514): Doreen Virtue, Charles Virtue: Books
Before I review this - I would like to point something out. Please keep in mind that amazon has 2 different identical books with this title by doreen. The covers and subtitle (notice how my subtitle and the link subtitle are different?) are completely different BUT inside the books - it is the same! Amazon really should warn people about this! I found out about this mishap from a customer review. Luckily this person was kind enough to warn people - so I did not buy 2 identical books. So just giving all of you a heads up as well.
This book discusses the many ways angels send you signs of hope, guidance and comfort. Signs such as feathers, clouds, pennies, numbers, voices, etc are discussed and there are numerous case studies and inspiring stories thruout the book.
Doreen also discusses how you can ask for a sign. There are also specific prayers that she provides for all areas of your life showing you the words to use to call forth signs for your specific needs.