recommended techniques
Here are some tips for you:
https://www.chess.com/blog/nklristic/the-beginners-tale-first-steps-to-chess-improvement
Good luck. 
Opening Principles is popular 😉. More so with intermediate players than beginners. If you google Opening Principles there are a number of good sites that will explain it. If you are on Chessable (google it), there is an excellent free course called Smithy's Opening Fundamentals.
check it out....lots of helpful resources for improving your chess, including openings...
https://www.chess.com/game/live/8728548919
crazy pawn defense, defense is my most favorite way to play bc its so good
Hi! My name is Lauren Goodkind and I'm a chess coach based in California! I have several tips to give you!
1) Ask questions before you make a move, such as,"If I move here, is it safe?" and "Can I safely capture a piece?"
2) Play with a slow time control, such as game in 30 minutes. You need time to think before you make your move.
3) I recommend a beginner's book for you: "Queen For A Day: The Girl's Guide To Chess Mastery". Readers get to play an entire chess game with a fictional character, Sophia. This book is available on Amazon.com and is endorsed by former US Women's Chess Champion, WGM Jennifer Shahade and other chess masters!
4) I also offer a free ebook on my website, www.ChessByLauren.com on how to win in chess.
5) I recommend the London Opening as white
I hope that this helps!
Dear Fsying,
I am a certified, full-time chess coach, so I hope I can help you. Everybody is different, so that's why there isn't only one general way to learn. First of all, you have to discover your biggest weaknesses in the game and start working on them. The most effective way for that is analysing your own games. Of course, if you are a beginner, you can't do it efficiently because you don't know too much about the game yet. There is a built-in engine on chess.com which can show you if a move is good or bad but the only problem that it can't explain you the plans, ideas behind the moves, so you won't know why is it so good or bad.
You can learn from books or Youtube channels as well, and maybe you can find a lot of useful information there but these sources are mostly general things and not personalized at all. That's why you need a good coach sooner or later if you really want to be better at chess. A good coach can help you with identifying your biggest weaknesses and explain everything, so you can leave your mistakes behind you. Of course, you won't apply everything immediately, this is a learning process (like learning languages), but if you are persistent and enthusiastic, you will achieve your goals.
In my opinion, chess has 4 main territories (openings, strategies, tactics/combinations and endgames). If you want to improve efficiently, you should improve all of these skills almost at the same time. That's what my training program is based on. My students really like it because the lessons are not boring (because we talk about more than one areas within one lesson) and they feel the improvement on the longer run. I wouldn't recommend you to learn openings so deeply because at beginner level it's completely enough to know the basic opening principles and middlegame plans. Of course, there are always ups and downs but this is completely normal in everyone's career.
I hope this is helpful for you. Good luck for your chess games!