I have been making mnemonics for katakana characters and am getting close to the end!
We just need ideas for katakana o (オ), sa (サ), wo (ヲ), and n (ン). If you come up with any ideas, please share with us 
Your idea could help many others !
Here are some examples if you haven’t seen yet:
コ (ko) as a handle of a coffee cup
ラ (ra) as a ramen bowl
頑張りましょう！