That might have been true of the original bone script characters, but over the millennia they have been stylized beyond recognition, and many new characters were created. Modern Japanese or Chinese is about as mnemonic as the typical icon set used in a GUI application.
However, most characters are composed of a few common components, called radicals, which can sometimes provide hints about the meaning. For example, the Chinese words 海 "sea", 波浪 "wave" and 渴 "thirsty" all contain the water radical ⺡. Similarly for 丝绸 "silk" and 缠绕 "wind around", which contain the thread radical ⺓.
Personally, I don't use any mnemonics, but I know someone who does, and he'd assigned each radical a memorable representation (e.g. the thread corresponds to Spiderman) and then he had a story linking a word to the components, so that 丝绸 would be about two Spidermen, one of which wraps himself in silk to use it as a ghost costume.
However, most characters are composed of a few common components, called radicals, which can sometimes provide hints about the meaning. For example, the Chinese words 海 "sea", 波浪 "wave" and 渴 "thirsty" all contain the water radical ⺡. Similarly for 丝绸 "silk" and 缠绕 "wind around", which contain the thread radical ⺓.
Personally, I don't use any mnemonics, but I know someone who does, and he'd assigned each radical a memorable representation (e.g. the thread corresponds to Spiderman) and then he had a story linking a word to the components, so that 丝绸 would be about two Spidermen, one of which wraps himself in silk to use it as a ghost costume.