I was thinking of しましょう or するが良い or something.
oh yeah! if it’s 備えをしようor 備えをしましょう, it being in volitional form would match some other stuff on the calendar, so that definitely makes sense
(今からやってみよう and つなごう, so maybe it is implying plain form?)
Wednesday, January the 4th:
失敗を生かそう
Let’s make the best of (our) mistakes.
I interpreted the に differently and came up with almost the opposite meaning:
Be prepared for good times
(i.e. don’t worry about the present bad times, better times will come)
But I agree that your translation makes more sense as a proverb.
Feels almost self-defeating to note that so far, this one is the most straightforward to understand
Nice to learn that 注意する mostly uses に though
Yah.
Often these signs use pure kanji (i.e. on the lines of 熊出没注意), but when a particle shows up, it’s に.
Friday, January the 6th:
実行はためらうな
Don’t hesitate to go for it.
(I’m starting to think that the proverbs in the month’s image are intended to be a theme for the whole month.)
Just do it!!
Saturday, January the 7th:
礼儀はまごころで
Gratitude comes from the heart?
Sunday, January the 8th:
すべてに全力で
With your full effort, you were able to produce a Zen lock (ぜんりょく). It’s a lock imbued with the power of Zen, meaning no one and nothing could possibly break it. It’s the one lock to rule them all.
100% in everything you do.
Don’t be afraid of mistakes/failure.
That’s what they probably told a certain doctor named Victor Frankenstein.