Buy a black suit, a black dress. Buy black shoes that you wear only with these clothes and a black tie and a handkerchief to carry in the clutch you only use when you wear that dress.
Keep mints in your pockets or purse.
Find a recipe and a charity. Make the meal or the donation when someone or something dies and take the food to the house of the grieving.
Have a baking dish ready.
Keep a box of note cards and books of poetry or memoirs of loss. Write notes of condolence and read words that tenderize your heart like a hammer. Write words that mean something.
Practice your handwriting.
Learn the damn language - it’s not Latin but it does take work. It’s been spoken since the garden. Practice it beforehand, workshop it with those who know, ruthlessly reject cliches or say nothing at all.
Show up, always show up.
Most of all, consider your own mortality, that you are but dust and so is everyone and everything you love. Remember all this is passing away but is worthy to be recklessly, relentlessly loved anyway.
Learn how to mourn.
Accept grief as part of life that no one will escape. Realizing this fact helps us bear our personal wounds and respond with Grace when others need us.