ワ

This character looks like a wine glass with no stem. It sounds like “wa”, the beginning of “wine”.

ヲ

Imagine that this character is half of a cooking wok. It’s spelled “wo” like the first two letters of “wok”.

ン

This looks like a crooked smiley face with a nose and no eyes. You can remember “no” from “no eyes” or “no” from “nose”.