The second tip is to sacrifice against overpowered opponents. If you get matched against a high-ranking opponent with fully maxed-out cards and legendary summoners, sometimes it is better to strategically throw the match. Therefore, instead of fighting a dead rubber battle, I submit a level 1 summoner and a single level 1 monster. With this approach, I control which cards I lose.
I totally agree and do the same. It's a bit sad that you have to play against those overpowered opponents, but sadly we can't change this.