How can I efficiently improve my chess rating


You say that the tactics are too easy, yet you only have a Tactics rating in the 600s and have failed half of your attempts. Right now, I wouldn't worry too much about watching lectures, just do lots and lots of tactics, because until you're able to get a tactics rating up from the 600s its unlikely you'll see your chess ratings improve.

Also, play long time controls and analyze your games afterward (look through the game, and figure out what mistakes you made and why you made them).
Possibly of interest:
Simple Attacking Plans by Fred Wilson (2012)
https://web.archive.org/web/20140708090402/http://www.chesscafe.com/text/review874.pdf
https://www.newinchess.com/Shop/Images/Pdfs/7192.pdf
Logical Chess: Move by Move by Irving Chernev (1957)
https://web.archive.org/web/20140708104437/http://www.chesscafe.com/text/logichess.pdf
The Most Instructive Games of Chess Ever Played by Irving Chernev (1965)
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
Back to Basics: Tactics by Dan Heisman (2007)
https://web.archive.org/web/20140708233537/http://www.chesscafe.com/text/review585.pdf
Discovering Chess Openings by GM John Emms (2006)
https://web.archive.org/web/20140627114655/http://www.chesscafe.com/text/hansen91.pdf
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/
https://www.mongoosepress.com/excerpts/OpeningsForAmateurs%20sample.pdf
Chess Endgames for Kids by Karsten Müller (2015)
https://chessbookreviews.wordpress.com/tag/chess-endgames-for-kids/
http://www.gambitbooks.com/pdfs/Chess_Endgames_for_Kids.pdf
A Guide to Chess Improvement by Dan Heisman (2010)
https://web.archive.org/web/20140708105628/http://www.chesscafe.com/text/review781.pdf
Seirawan stuff
http://seagaard.dk/review/eng/bo_beginner/ev_winning_chess.asp?KATID=BO&ID=BO-Beginner
https://www.chess.com/article/view/book-review-winning-chess-endings
https://web.archive.org/web/20140627132508/http://www.chesscafe.com/text/hansen173.pdf
http://www.nystar.com/tamarkin/review1.htm

You need to quit playing blitz and play rapid. I was an 800 rapid player when I first started. In my first year I made it to 1600 and I played zero blitz in that time. Learn to play chess, then learn to play blitz.

Just don't be one of those people that will say, "You cheated! My pawn moved twice you can't take it when it's not there!" I know a guy who plays perfect chess online but I can beat OTB and he doesn't even know en passant!

Still no one here has told the OP the basics of a chess game. Could someone let him know?
What are "THE BASICS OF A GAME OF CHESS"??

Possibly of interest:
Simple Attacking Plans by Fred Wilson (2012)
https://web.archive.org/web/20140708090402/http://www.chesscafe.com/text/review874.pdf
https://www.newinchess.com/Shop/Images/Pdfs/7192.pdf
The book just tells the basics. I like chess for dummies better because chess for dummies talks about things you will use when you are over 2000+ rating. Sure, you will still use the stuff in this book at a 2000+ rating as well, however, I think a lot of this stuff is common sense and can be learned by simply playing a few games of chess with an e4 e5 pawn opening. Not that the stuff written in chess for dummies isn't common sense for the seasoned chess player, however, those sort of things, talked about in chess for dummies are not abstract ideas that only work if your opponent blunders, but are tools you are going to use for the rest of your chess playing career.
Logical Chess: Move by Move by Irving Chernev (1957)
https://web.archive.org/web/20140708104437/http://www.chesscafe.com/text/logichess.pdf
Good book!
The Most Instructive Games of Chess Ever Played by Irving Chernev (1965)
https://chessbookreviews.wordpress.com/tag/most-instructive-games-of-chess-ever-played/
Good book!
Winning Chess by Irving Chernev and Fred Reinfeld (1949)
https://web.archive.org/web/20140708093415/http://www.chesscafe.com/text/review919.pdf
Good book!
Back to Basics: Tactics by Dan Heisman (2007)
https://web.archive.org/web/20140708233537/http://www.chesscafe.com/text/review585.pdf
Good book!
Discovering Chess Openings by GM John Emms (2006)
https://web.archive.org/web/20140627114655/http://www.chesscafe.com/text/hansen91.pdf
A bit basic. Your better off paying for a membership here for a month and reading the articles and watching the videos on the opening beginner section of the study plans.
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/
https://www.mongoosepress.com/excerpts/OpeningsForAmateurs%20sample.pdf
I don't know anything about that book but I will look into it!
Chess Endgames for Kids by Karsten Müller (2015)
https://chessbookreviews.wordpress.com/tag/chess-endgames-for-kids/
http://www.gambitbooks.com/pdfs/Chess_Endgames_for_Kids.pdf
Haven't read it either, might pass on this one...
A Guide to Chess Improvement by Dan Heisman (2010)
https://web.archive.org/web/20140708105628/http://www.chesscafe.com/text/review781.pdf
Probably the best beginner book here that stirs the beginner in the right direction and also gives the beginner a good thinking algorithm for chess.
Seirawan stuff
http://seagaard.dk/review/eng/bo_beginner/ev_winning_chess.asp?KATID=BO&ID=BO-Beginner
https://www.chess.com/article/view/book-review-winning-chess-endings
https://web.archive.org/web/20140627132508/http://www.chesscafe.com/text/hansen173.pdf
http://www.nystar.com/tamarkin/review1.htm
Have no idea about this stuff.