You might remember the meaning of the character 刚 with this easy mnemonic:
A man is hiding under an upside down cardboard box (冂) because he has a hard time repaying his debts. Oh no! A creditor is after him with a razor (刂) knife and slashing (丿) the box.
Using mnemonics to remember the meaning of Chinese characters like has a huge impact on how long to learn Mandarin it takes.