You might remember the meaning of the character 合 with this easy mnemonic:
Through word of mouth (口), you heard about this one (一) really cool book. You don't know what it's about, but both men (人) and women want to read it. This includes you too. You finally got your hand on it. It's impossible to close and put it down. You finished reading it in one sitting.
Using mnemonics to remember the meaning of Chinese characters like has a huge impact on how long to learn Mandarin it takes.