You might remember the meaning of the character 胶 with this easy mnemonic:
I wish to go to the moon (月) one day and glue this lid (亠) on the moon's surface. I bet eight (八) dollars that the lid will stay glued, otherwise you can slash (丿) my tires.
Using mnemonics to remember the meaning of Chinese characters like has a huge impact on how long to learn Mandarin it takes.