What is the best first move for a beginner?

1.e4. It takes a central square, opens lines for the bishop on f1 and the queen at the same time, and leads to positions where the pieces come out and hit each other, which is the kind of game you learn from. 1.d4 is just as good and a little quieter. Either one beats 1.a3 by a mile.

How do I stop losing pieces?

Make one question part of every single move: after your opponent moves, what does that move now attack? Then look for your own pieces that nothing is defending. It takes five seconds and it is most of the gap between 800 and 1200. Doing it on the obvious moves too, when you are sure there is nothing there, is the hard part.

Should beginners learn chess openings?

Learn the principles, not the lines. A centre pawn, knights and bishops out, castle by move ten, do not move the same piece twice without a reason, do not bring the queen out early. That will serve you for years. The one exception is a specific trap you keep losing to, like Scholar's mate, which is worth ten minutes of your time.

How to win at chess as a beginner

Almost every game I go through with a beginner has the same losing move in it, and it is never an opening mistake. It is a piece left standing where it can be taken for nothing. Fix that one thing and your results move before you have learned any chess at all. Then take the pieces your opponent leaves, and you win most games without ever finding a clever idea.

Five habits, in the order they pay off.

After every move your opponent makes, ask what that move now attacks. Not what it looks like it is doing: what it attacks. A bishop dropping back to b3 is aiming at f7, and the pawn on f7 is defended only by your king.
Develop and castle. Knights and bishops off the back rank in the first eight moves, king castled by move ten. Do not chase pawns with the queen while your rooks are still asleep in the corners.
Take free material and count it. A knight for nothing is three pawns’ worth. Two of those and the game is over at this level. Learn the piece values so you can tell a good trade from a bad one in a second.
Know the traps that kill beginners, starting with Scholar’s mate.
Learn two checkmates properly, so that being a queen up actually turns into a point.

The trap you must not lose to

Scholar’s mate is four moves long and it has ended more beginner games than every opening in the books put together.

Scholar's mate: 1.e4 e5 2.Bc4 Nc6 3.Qh5 Nf6 is the losing move, and 4.Qxf7 is checkmate. The bishop on c4 and the queen on h5 both hit f7, which the king alone defends.

Mate. The queen on f7 is protected by the bishop on c4, the king on e8 cannot take her and has no square, and nothing can capture on f7 or block. Black's knights on c6 and f6 are both looking the wrong way.

The cure is to look at f7 (f2 if you are White) every time an enemy bishop or queen turns towards it. Against 3.Qh5, play 3…g6. The pawn attacks the queen, so she has to move again, and after 4.Qf3 the mate on f7 is threatened all over again: 4…Bg7 loses instantly to 5.Qxf7. The move that holds is 4…Nf6, which does not defend f7 at all but stands in the queen’s way on the f-file. White has nothing, Black has two pieces out and a pawn on g6, and the queen on f3 is sitting on the square White’s own knight wanted. Full treatment on how to defend against Scholar’s mate.

The general version of that habit is the one that matters more: every enemy piece that has just moved is pointing somewhere, and f7 and f2 are the softest squares on the board because only the king defends them at the start.

Finish what you win

Being a queen up is worth nothing if the game ends in a draw because you could not deliver mate. I have watched a nine-year-old stalemate an opponent three times in one tournament with a queen and two rooks on the board.

So learn king and queen against king until you can do it in ten moves without thinking, then king and rook against king. Two evenings, and you will convert every won position for the rest of your life.

What to practise between games

Two things, and nothing else for the first few months. Puzzles where a piece is simply hanging, because spotting free material is the skill that wins beginner games: the hanging piece puzzles are exactly that. And mate in one, until you see checks before you see anything else.

If you keep giving material away despite all this, the problem is a process problem rather than a chess problem, and how to stop blundering is written for it.