Many of us want to improve at chess. Actually, make that ALL of us. But some of us might feel stuck, or might not be sure what is the best way to improve. While I may not have a definitive answer, I believe that having a wide variety of studying methods is very beneficial. After all, you never see a GM only studying his endgames, do you? A good player must work on many aspects of his game. Therefore, I have put together a nice list of 25 ways to improve at chess. Each method has a short description. Hopefully you will be inspired by one of these methods and get better at chess! Have fun! 
Contents
Note: These methods are not ranked by importance or efficiency. Everyone learns differently! Develop your own training system that works for YOU. 
- Analyze Your Games
- Play Online Live Chess
- Play Daily Chess
- Play vs Computer
- Play OTB Tournaments
- Solve Tactics Online
- Read Tactics Books
- Read Endgame Books
- Play Endgames vs Computer
- Read Middlegame/Strategic Books
- Use Opening Explorer
- Create Opening Files for Your Repertoire
- Review Your Openings
- Play Vision
- Play Solo Chess
- Read Articles
- Read Blogs (Yay!)
- Watch Videos
- Watch Streams
- Play Chess Variants
- Take Lesson Courses
- Discuss with Others
- Get a Training Partner
- Get a Coach
- Ask Questions!
A great way to improve at chess. Analyzing your games right after playing them is great, as you can reflect on your mistakes and remember that information for a long time. It's not enough to just play games!
Relatively obvious, but it's never a bad idea to hop onto chess.com and play a couple of games. If you want serious improvement, I would recommend 10 min rapid games.
Better for people who do not have too much time to spend at once, and would rather spend time in bursts of a few minutes per move. This is great for practicing openings, as you can analyze lines and view opening theory during the game.
Many people don't like playing against the computer, because sometimes they play very odd moves. However, this is good sometimes if you want to simulate a player's exact rating level, and to get a taste of what it's like to play someone who doesn't think the same way that you do.
Obviously, this is a bit hard right now with the pandemic, but playing OTB tournaments is important as well. It's very different from online chess, as the atmosphere, playing hall, people around you, distractions, and body language can all affect the game.
Very convenient and quick. You can simply go online and solve some puzzles, and it's great! However, I would still recommend buying a tactics book, namely The Woodpecker Method by Hans Tikkanen and Axel Smith if you would really like to up your tactical abilities.
Well, I've already mentioned this above, but buying a book to solve puzzles from has its benefits. You can focus on certain motifs, and get positions taken out of real games! Sometimes it is simply best to walk away from a screen and sit down on the couch to solve some puzzles.
When it comes to endgames, books are the best (in my opinion!). I would recommend Silman's Complete Endgame Course and Dvoretsky's Endgame Manual to learn endgames. It's important to learn how to win once you've outplayed your opponent in the earlier stages of the game. Also, you can save more positions by heading towards trickier endgames.
A great way to practice your technique! You can set up a specific position to play against the computer and see how well you fare.
10. Read Middlegame/Strategic Books 
This is kind of broad, but there are many great books out there to read to improve your understanding of chess as a whole. There are too many to name, but I'd like to mention the Grandmaster Preparation Series by Jacob Aagaard.
For more information, check this out.
A great tool to explore openings and see how great players play! You can use this in daily chess and it can be found at https://www.chess.com/explorer.
12. Create Opening Files for Your Repertoire 
This is pretty important, especially if you are an intermediate to advanced player. As you progress, you will need to create files in order to hold your opening variations. It can be too hard to remember all of them sometimes, so creating pgn files using a program like chessbase is pretty important.
Reviewing your openings is key! While you shouldn't blindly memorize opening lines, there are some variations where you need to make a few crucial moves, and then the smoke clears. It's still most important to understand the key ideas of an opening though...
Vision is a very interesting tool and is great to work on your vision of the board. When calculating, many times it is hard to imagine where pieces can move and such. To work on this, you can go to https://www.chess.com/vision.
Solo Chess is a very cool game on chess.com to help you improve both calculation and conceptual understanding of how pieces work together. You can find it at chess.com/solo-chess
For more, check out this blog and this video!
Articles are a great way to leisurely read about chess but also improve at the same time. Some of my favorite chess.com articles are included below:
https://www.chess.com/article/view/chess-miracle
https://www.chess.com/article/view/queens-gambit-every-chess-position
https://www.chess.com/article/view/how-to-become-a-chess-master
I bet you've heard of this one before. To all of you wonderful readers, I say thank you!
Videos are a great way to take in information in a different way. Sometimes bashing your brain out by solving puzzles or playing online games can be too much. Relaxing with a nice video on chess.com or youtube can be refreshing and very helpful.
We all know @Hikaru, right? Well... go watch his stream. Very entertaining and educational as well. Seriously though... it's not a bad idea to check out some chess streams while you slowly eat dinner...
This one is interesting. How can you improve at chess by playing 3 check, or king of the hill? Well, you can! While some variants are more helpful than others, here's a couple notable ones that can somewhat help you improve:
1. Blindfold Chess - helps imagination, vision, and calculation
2. 3 Check - Increases awareness of king safety and square weaknesses
3. Horde - Maybe you've played as white and realized that pawns in fact do not move backwards!
And many more. Obviously this isn't the most effective way to improve at chess, but it's fun!
This goes without saying. Learn from others who are better than you. There's lots of great courses out there by many wonderful coaches and teachers.
Discussing with others can be eye-opening. You can discuss games, positions, openings, and more! Sometimes it's important to just get some other peoples' perspectives.
This is more for advanced players, but sometimes it's nice to have someone to study with and play against consistently. They can help you identify your weaknesses and strengths, and vice versa.
Obviously not of top priority, since if done right you can improve just as well by yourself. But if you are finding that you are struggling after trying many different things, many you just need an experienced coach to help guide you in the right direction.
By far the most important one. Have a curious mind! If you're always wondering why things are the way they are or why a move is best, you will learn! It's important to have the passion to learn! 
Everyone who plays chess wants to be good at chess. And there are an endless number of methods that bring about improvement. However, these methods are inefficient, and often costly. So, how does one get good at chess quickly without having to spend a dime? All you have to do is follow the steps in this post. I promise to cut the bull and get to the juicy stuff.
The most common reason beginners lose chess games is because they hang pieces. Giving away one's pieces makes it incredibly difficult to do anything; defending and checkmating become almost impossible for the average beginner. So, we must eliminate that. Here are my two solutions.
1. DO TACTICS
Tactics help build pattern recognition. Therefore, you will train your brain to pick up on hanging pieces and quick mates.
2. Before every move, ask yourself these two questions: What checks and captures does my opponent have? And what checks and captures do I have?
Alright moving on...
Now you blunder less. What is there now to improve? Easy. You need to know how basic endgame checkmates work. So, learn them. Here is a list of the important ones:
1. Rook + Rook + King vs King
2. Rook + King vs King
3. Queen + King vs King
4. 2 pawns + King vs King
5. 1 pawn + King vs King
That's it. Beginners will seldom encounter other structures, so it is pointless to learn them until at least 1700 ish.
Next up, you need to learn openings, and how to deal with your opponent's plans. Easy. Don't learn any openings (at least as white). Instead, opt for systems for quick improvement. Systems allow players to go on autopilot and still move like a Grandmaster.
Systems I recommend:
London System
King's Indian Attack
Notice how there aren't any good systems for Black? It is unfortunate. Instead, I prescribe learning 2 (and only 2) openings as black. The French Defense against e4 (learn the Advance Variation, the Rubinstein, and the Exchange variation) and the rat against d4 will prepare you well for all opponents.
Next up is the middle-game. Easy enough. Just learn the basic positional principles listed below:
1. Space
2. Outposts
3. Good Bishop vs Bad Bishop vs Good Bad Bishop vs Bad Good Bishop
4. Minority attack
5. Pawn structures and how they work
6. Pawn weaknesses and how to exploit them
7. tempo (counting-up opening tempi and counting-down endgame tempi)
Finally, ask yourself this question after every move (both for yourself and your opponent):
What does this move do, and what does this move no longer do?
That's it. That's how to get good fast. Just learn this. And to apply it, just play a ton of blitz games to hammer in these principles.
(note: This article assumes knowledge of piece movement and castling)