How to: Write Algebraic Notation

Update 6/4/2017:
Additional notation:
=    equal.
+= slight advantage to White.
+-  significant advantage to White.
=+ slight advantage to Black.
-+  significant advantage to Black.

The following instruction set is excerpted from Chess Puzzle Learning Levels:

Algebraic notation is most widely used to write chess moves, and the notation of choice here. A brief description is included.  For each move (in order), write:

1. The piece moving: K for king; Q, queen; R, rook; B, bishop; N, knight. No letter is written for a pawn.

2. Only if more than one piece of the same kind can reach a square: write the differing file or rank (preference given to differing file). In very rare cases, both the differing file and rank must be written.

3. Only if the move is a capture: write an x. With pawn captures, the original file of the pawn precedes the x (e.g. exf4).

4. Write the piece's destination square, file then rank (e.g. e4, see diagram to the right).

5. Conditional: For castling, skip 1-4 and write O-O (kingside castle), O-O-O (queenside castle). If the move is a promotion, an = sign is appended with the letter of the piece promotion following (e.g. e8=Q). If the move is check, a + is appended at the very end; if checkmate, #.

Commentary: After 1-5 are written, specific symbols are optionally used for commentary; more are used, but not in this text:

! - good move, surprising move.
!! - very good move, very surprising move.
? - questionable move.
?? - blunder.
!? - interesting move.
?! - interesting but questionable move.
(D) - the position after the previous move is featured in the diagram.