I think the best books for you are tactics books. You say you already have tactics books at home but haven't looked at them enough, your problem is not that you need more books, your problem is that you need to hit the ones u have.
What type of chess book should I get?

So what type of book should I buy? I briefly looked at some of the tactics books, some of which I had and some of which I didn't. I need to read in more detail the books that I do have.
Openings:
FCO: Fundamental Chess Openings by Paul Van Der Sterren
Endgame (if you want supplements to Silman):
Understanding Chess Endgames by John Nunn
or
Dvoretsky's Endgame Manual by Mark Dvoretsky
(start with the the coloured part, the rest is for life!)
If the reason you have not been through your tactics books is that they are too difficult, buy some easier ones and study them again and again before advancing. If the ones you have is only diagrams and no text you might consider some that try to teach (many to choose from):
Winning Chess Tactics, revised by Yasser Seirawan
Chess Tactics for the Tournament Player (Third Edition) by Sam Palatnik and Lev Alburt
Learn Chess Tactics by John Nunn
Course in Chess Tactics by Dejan Bojkov and Vladimir Georgiev
Improve Your Chess Tactics: 700 Practical Lessons & Exercises Paperback by Yakov Neishtadt
Chess Tactics from Scratch, 2nd ed.: Understanding Chess Tactics by Martin Weteschnik
To get something of everything consider starting on the books by Yusupov :
Build Up Your Chess 1: The Fundamentals
by Artur Yusupov
Good luck!

Also, are there any specific authors on endgames whose books I should be looking for in the store? Thanks, guys.
If you want just one large all purpose endgame book for life Silman's Endgame Course covers everything up to Master Level.
Very good is John Nunn's Understanding Chess Endgames he has two larger works on the endgame if you ever want to go deeper down the rabbit hole
The Russian Endgame Handbook by Illya Rabinovitch
Some troll on Amazon trashed it said he hated it but I've read this Russian book it's good stuff I don`t know what he`s talking about.
100 Endgames you must Know from Jesus De Villa from New in Chess is very good
Just the Facts by Lev Alburt and Nicolay Krogius
Only what you need to know and the essential stuff written by two Endgame Generals one of them was Spassky`s Coach in 1972 you can`t go wrong here.
How to Play Chess Endings by Zonosko Borovosky
This is a much older work from 1940 from Dover Books but I highly recommend it he teaches principles and understanding of Chess over memorization it`s in descriptive notation good stuff!

Unless you have plans to pursue GM norms in the near future, Silman's book will give you more than you'll ever need to know for a lifetime of endgames.

Logical Chess Move By Move is a good one.
Really though, at your level, you need to concentrate on reading and rereading the books you already have.
I would stick to tactics and endgames until you are a couple hundred points higher.

Also, are there any specific authors on endgames whose books I should be looking for in the store? Thanks, guys.
100 Endgames you must Know from Jesus De Villa from New in Chess is very good
@dpnorman: Follow the recommendation by alec98 to buy 100 Endgames You Must Know by Jesus de la Villa.
alec98, I see your account is new here. Welcome.

Here's an article I wrote on foundational books. If you don't have any of the ones listed, I recommend checking them out:
http://www.betterchesstraining.com/2014/05/chess-books-for-beginnners.html
Hope you find it helpful.
Hey, guys. I am playing in the Eastern Open and there is a decent chess bookstore here full of different chess books that I could buy. In the last round, I got an upset over a better opponent, which means I get $25 off my next purchase at the store. I also just finished another game where I defeated a higher rated opponent, so I may get another upset discount. I want to know what sort of book I should buy.
At my house, I have a bunch of tactics books which I don't seem to look at enough, a couple of Jeremy Silman's middlegame strategy books, Silman's Endgame Manual, and a couple other books on various topics. I don't have opening or endgame books other than Silman's book. With a good performance in this tournament, I can raise my rating into the 1200's, which gives you an idea of my skill level. I think it's important to note that I did kinda mess up a won endgame earlier in the tournament to get a draw in a better position so perhaps an endgame book is in order...but if I get both discounts, what should I do with the other one. Also, are there any specific authors on endgames whose books I should be looking for in the store? Thanks, guys.