You might remember the meaning of the character 警 with this easy mnemonic:
A flower (艹) store alerted the police when two (二) people with bandages wrapped (勹) around their heads only showing their mouths (口) and eyes slashed (丿) open the store windows. They also kicked at the rubbish bins and sent the lids (亠) and rubbish everywhere.
Using mnemonics to remember the meaning of Chinese characters like has a huge impact on how long to learn Mandarin it takes.