My first few books were "Winning Chess Strategy" and "Winning Chess Tactics" by Yasser Seirwan. I think you may be able to find PDFs of them with a google search.
How to Learn Chess Strategy
I was unable to find either of those but I did find "The Complete Book of Chess Strategy" by Jeremy Silman, which according to Amazon reviews is a good book for beginners.
I am unable to challenge you because your account is set to only accept challenges of someone with a ranking of at least 1300 so can you challenge me?
I often suggest Simple Attacking Plans by Fred Wilson (2012)
https://web.archive.org/web/20140708090402/http://www.chesscafe.com/text/review874.pdf
Logical Chess: Move by Move by Irving Chernev
https://web.archive.org/web/20140708104437/http://www.chesscafe.com/text/logichess.pdf
The Most Instructive Games of Chess Ever Played by Irving Chernev
https://chessbookreviews.wordpress.com/tag/most-instructive-games-of-chess-ever-played/
Winning Chess by Irving Chernev and Fred Reinfeld (1949)
https://web.archive.org/web/20140708093415/http://www.chesscafe.com/text/review919.pdf
Discovering Chess Openings by GM Johm Emms (2006)
https://web.archive.org/web/20140627114655/http://www.chesscafe.com/text/hansen91.pdf
Openings for Amateurs by Pete Tamburro
http://kenilworthian.blogspot.com/2014/05/review-of-pete-tamburros-openings-for.html
Chess Endgames for Kids by Karsten Müller (2015)
https://chessbookreviews.wordpress.com/tag/chess-endgames-for-kids/
A Guide to Chess Improvement by Dan Heisman (2010)
https://web.archive.org/web/20140708105628/http://www.chesscafe.com/text/review781.pdf

http://www.amazon.com/Winning-Chess-Strategies-Everyman/dp/1857443853
But yeah, Silman's books are always pretty good.

I love the chess mentor courses, and is almost everything I know + the videos on chess.com (but mainly chess mentor). Never read more than 20 pages in a chess book! Yet, I beat titled players.
Get a strategy book as it is structured and systematic in helping you improve. And in case you forget something, you can just look at your book.
Get Winning Chess Strategy for Kids by Coakley. Don't let the title fool you. It's a great book. It's one of the best book out there for your level. How I wish I have this book during my starting out years.
http://www.amazon.com/Winning-Chess-Strategy-Kids-Coakley/dp/1895525055

http://www.chess.com/forum/view/general/how-to-analyze-position-scientifically-part-1
It will help you very much.
I have known how to play chess (by that I mean the rules) since I was young but never learned more than basic strategy. However, recently I have started playing chess a bit more seriously and am planning on joining the chess team at my school. I am hoping that someone can steer me along the right path to learning the game. Could you recommend a good book for me to read, or should I go about learning another way, such as a chess-teaching app? Any help would be great.