The tips your recommending seems a little outdated.
I have stopped telling beginners to learn Rook & Pawn End Games because it’s pretty pointless.
A beginner winning 1 game in the End Game doesn’t make up for them losing 10 games in Opening.
Their rating is still not going to increase.
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If you told a beginner to resign any game which reaches past 20 moves, Than taught them how to play the first 20 moves in a game exceptionally well.
Their overall rating would increase.
If you look at a lot of beginner profiles, you will see a lot of loses & wins.
The majority of games will be resigned at around move 10.
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Short time controls are bad idea as well.
Most beginners play fast even in longer time controls which is bad habit.
You really want them to play long time controls.
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I’m not sure why you grouped your tips for Intermediate players & beginner players.
Intermediate players have a lot of other issues which they should focus on which are pretty unrelated to beginners.
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