How to best utilize opening theory

Hello, 

I am currently an 800~ player and am looking to improve in all ways. I watch youtube videos, play games, do tactics and chess.com lessons and my rating did improve.

I always struggled with opening on the premise that you learn lines but as soon as someone does a move that is not in the opening you've learned your knowledge is now made redundant (to me anyway!). To solve this issue I purchased starting out 1d4! by John Cox and started reading over the queens gambit however the same problem occurs and I feel like im approaching openings in the wrong way.

For example, the black plays the modern defence in this book but I have never played anyone who has played the modern opening... so how do apply this theory to my game when somebody plays a completely different move?

Yes, the Modern defense is for advanced players who know how to play in the hypermodern setting.  Unfortunately, I don't know any opening books written especially for low-rated players. Maybe kindaspongey can help, he knows tons of useful bibliographical references. 

There are a couple of opening books written for beginners, eg. James Eade's Chess Openings for Dummies or William Aramil's Complete Idiot's Guide to Chess Openings.  Another type of book you might find useful are those with "move by move" explanations, eg. Irving Chernev's Logical Chess Move by Move.  There are move by move books on particular openings, eg. Neil McDonald's Ruy Lopez Move by Move.

I think its mainly the problem of preparing an opening, trying to remember the moves and then my opposition just playing something completely off book.

I guess that is just the nature of chess and maybe I am taking opening theory a bit too literally.

At the 850 level, I don't think you need to worry about remembering lines.  Move your e- and d-pawns to let your bishops out.  Develop a new piece with each move until your back rank is clear, so you can castle.  Move your pieces and pawns as close to the centre of the board as you can get without losing material.  Bring out your worst placed piece.  Don't move the same piece twice if you can avoid it.  Don't bring your queen out too early as she'll get chased around.  Try to calculate a move or two ahead by guessing how your opponent will respond to your move.  Watch out for checkmates, forks, skewers, pins, etc.  Analyze your games afterwards, trying to figure out where you went wrong.

Not sure how old you are, but there are also the books John Watson's Chess Openings for Kids and Charles Hertan's Basic Chess Openings for Kids.

Well-written, U could easily write a good book for beginners. 

Hi, yes my profile picture confuses many and I have tried to change it. I'm 21 and just slightlyy bigger than I was in that photo. 

Thank you for the tips guys and I cna only hope to carry them onto the board! Maybe I will pick up the book I purchased at a later date!

XXX

"... there will come a time, whether on move two or move twenty, when your knowledge of theory runs out and you have to decide what to do on your own. ... sometimes you will leave theory first, sometimes your opponent. ... It happens in every well-contested GM game at some point, usually a very significant point. ..." - IM John Cox (2006)

For someone seeking help with openings, I usually bring up Openings for Amateurs by Pete Tamburro (2014).
http://kenilworthian.blogspot.com/2014/05/review-of-pete-tamburros-openings-for.html
https://chessbookreviews.wordpress.com/tag/openings-for-amateurs/
I believe that it is possible to see a fair portion of the beginning of Tamburro's book by going to the Mongoose Press site.
https://www.mongoosepress.com/catalog/excerpts/openings_amateurs.pdf
Perhaps LLREGS would also want to look at Discovering Chess Openings by GM John Emms (2006).
"... For beginning players, [Discovering Chess Openings] will offer an opportunity to start out on the right foot and really get a feel for what is happening on the board. ..." - FM Carsten Hansen (2006)
https://web.archive.org/web/20140627114655/http://www.chesscafe.com/text/hansen91.pdf
"There is no such thing as a 'best opening.' Each player should choose an opening that attracts him. Some players are looking for a gambit as White, others for Black gambits. Many players that are starting out (or have bad memories) want to avoid mainstream systems, others want dynamic openings, and others want calm positional pathways. It’s all about personal taste and personal need.
For example, if you feel you’re poor at tactics you can choose a quiet positional opening (trying to hide from your weakness and just play chess), or seek more dynamic openings that engender lots of tactics and sacrifices (this might lead to more losses but, over time, will improve your tactical skills and make you stronger)." - IM Jeremy Silman (January 28, 2016)
https://www.chess.com/article/view/opening-questions-and-a-dream-mate
https://www.chess.com/article/view/picking-the-correct-opening-repertoire
http://chess-teacher.com/best-chess-openings/
https://www.chess.com/blog/TigerLilov/build-your-opening-repertoire
https://www.chess.com/blog/CraiggoryC/how-to-build-an-opening-repertoire
https://www.chess.com/article/view/learning-an-opening-to-memorize-or-understand
https://www.chess.com/article/view/the-perfect-opening-for-the-lazy-student
https://www.chess.com/article/view/3-ways-to-learn-new-openings
https://www.chess.com/article/view/how-to-understand-openings
https://www.newinchess.com/media/wysiwyg/product_pdf/9035.pdf
https://web.archive.org/web/20140627110453/http://www.chesscafe.com/text/hansen169.pdf
https://www.newinchess.com/media/wysiwyg/product_pdf/9029.pdf
https://www.chess.com/article/view/has-the-king-s-indian-attack-been-forgotten
https://www.newinchess.com/media/wysiwyg/product_pdf/7277.pdf
https://www.newinchess.com/media/wysiwyg/product_pdf/9033.pdf
https://www.newinchess.com/media/wysiwyg/product_pdf/9050.pdf
https://web.archive.org/web/20140627104938/http://www.chesscafe.com/text/hansen159.pdf
https://web.archive.org/web/20140627022042/http://www.chesscafe.com/text/hansen153.pdf
https://web.archive.org/web/20140627132508/http://www.chesscafe.com/text/hansen173.pdf
"... Overall, I would advise most players to stick to a fairly limited range of openings, and not to worry about learning too much by heart. ..." - FM Steve Giddins (2008)
"... Once you identify an opening you really like and wish to learn in more depth, then should you pick up a book on a particular opening or variation. Start with ones that explain the opening variations and are not just meant for advanced players. ..." - Dan Heisman (2001)
https://web.archive.org/web/20140626180930/http://www.chesscafe.com/text/heisman06.pdf
"... To begin with, only study the main lines ... you can easily fill in the unusual lines later. ..." - GM John Nunn (2006)
"... I feel that the main reasons to buy an opening book are to give a good overview of the opening, and to explain general plans and ideas. ..." - GM John Nunn (2006)
"... If the book contains illustrative games, it is worth playing these over first ..." - GM John Nunn (2006)
"... the average player only needs to know a limited amount about the openings he plays. Providing he understands the main aims of the opening, a few typical plans and a handful of basic variations, that is enough. ..." - FM Steve Giddins (2008)
"... For inexperienced players, I think the model that bases opening discussions on more or less complete games that are fully annotated, though with a main focus on the opening and early middlegame, is the ideal. ..." - FM Carsten Hansen (2010)
"... Everyman Chess has started a new series aimed at those who want to understand the basics of an opening, i.e., the not-yet-so-strong players. ... I imagine [there] will be a long series based on the premise of bringing the basic ideas of an opening to the reader through plenty of introductory text, game annotations, hints, plans and much more. ..." - FM Carsten Hansen (2002)
https://web.archive.org/web/20140627055734/http://www.chesscafe.com/text/hansen38.pdf
"The way I suggest you study this book is to play through the main games once, relatively quickly, and then start playing the variation in actual games. Playing an opening in real games is of vital importance - without this kind of live practice it is impossible to get a 'feel' for the kind of game it leads to. There is time enough later for involvement with the details, after playing your games it is good to look up the line." - GM Nigel Davies (2005)

At 800 or 1000, few of your opponents are going to be playing standard openings. I would work on just understanding basic opening principles (play 1. e4 or 1. d4, knights first, then bishops, move your queen up but don't put her out there to be captured, castle and connect your rooks). If you want to learn openings at 1000, I wouldn't try to learn more than 8-13 moves as you and your opponents will be out of book pretty quickly. It actually would be worth more of your study time to learn checkmate patterns, practice tactics (if you can afford a paid membership here you get unlimited tactics, but you can find tactics books) and learn some endgame basics (I like Silman's Complete Endgame Course because he teaches endgame skills based on your rating).

Here's a link to Daniel Renschs' nice summary of basic opening principles: https://www.chess.com/article/view/the-principles-of-the-opening

 Well first of all you need to get to a level where learning openings give you an advantage that you can properly convert if you just blunder a knight right after you run out of theory there really isn't much point to memorizing openings.

"... For beginning players, [Discovering Chess Openings by GM John Emms] will offer an opportunity to start out on the right foot and really get a feel for what is happening on the board. ..." - FM Carsten Hansen (2006)
https://web.archive.org/web/20140627114655/http://www.chesscafe.com/text/hansen91.pdf

Some have the desire to avoid disadvantage.