豕 is a pictograph of a pig, with the modern form preserving a stylized head, body, legs, and tail.
Meaning mnemonic
The top horizontal stroke suggests the pig's head, the curved strokes its body and legs, and the final sweeping stroke its tail. Put together, 豕 is a pig.
Reading mnemonic
For シ, imagine a pig sitting in a field of sheaves (シ): sheaves -> シ, and the pig is resting among them.
