Are you writing like a person who wants to write but has lost their pen in a snowstorm that came from a sky filled with clouds that were like cotton wool that had been dipped in ink and that would explain where your pen had gone?
That chair you're sitting on: is it hard like a nail but that can't be right because nails are pointy and it's best not to sit on them if you can avoid it so maybe it's hard like a celebrity's heart but who'd want to feel that squishing round under their buttocks? Or perhaps it's soft instead. Soft like ...
It's OK, I haven't gone (completely) insane. I'm talking about deciding when you need a simile and choosing the best image. The above was inspired by this wonderful collection.