There are some nice fresh materials published by Chess in Schools and Communities: https://www.chessinschools.co.uk/chess-at-home
Chess Tips
| OPENING TIPS: |
(Fine) 10. Do not sacrifice without a clear and adequate reason, eg.: <br>* it secures a tangible advantage in development <br>* it deflects the opponent's queen <br>* it prevents the opponent from castling <br>* it enables a strong attack to be developed |