You might remember the meaning of the character 许 with this easy mnemonic:
I have to give a speech (讠) tomorrow and I still haven't memorized what I have to say. It's going to be on how the company slashed (丿) everyone's salary in half and leaving us all out to dry (干). I don't think the company will allow me to give any more speeches after this one.
Using mnemonics to remember the meaning of Chinese characters like has a huge impact on how long to learn Mandarin it takes.