I haven't played chess in a long while. I would say learn the fundamentals of openings and the end game.
There are openings which are meant to quickly win, such as Scholar's Mate and Blitzkreig, but an experienced opponent will not fall for these. However, this was the first lesson to me so that I don't fall for the same tactics.
Kids' Book of Chess and Chess Set, Book by Harvey Kidder was my first book on the game which taught me this, and included an example where you lose after a standard opening, because of a mistake in the response. Don't let the fact that it's for kids fool you. It was quite insightful.
Bobby Fisher Teaches Chess is a good interactive resource for endgame, going into detail on back-rank mates (calculating the count of attackers, useful/useless interpositions, king moves), displacing defenders, and demolishing pawn cover. It has good examples and asks if you can mate and how. With back-rank mates, for example, you check moves ahead to ensure the planned sacrifices result in a win (a "forced mate")
Developed byBookup, Inc.PlatformDOSPublished byMission StudiosReleased1994GenreEducational, SimulationGameplayChessPerspectiveTop-downEducationalMath /...
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Other general advice over the years are as follows.
* "To take is a mistake." (Think over if this opens the game or trades to your disadvantage, or loses tempo)
* Control of the four central squares is generally good, with the Queen especially
* Don't touch king side pawns (again, generally speaking. you might g2 to g3 for a nook for the king to hide in after castling)