Just because it’s Easter and we’re busy stuffing ourselves with chocolate and hot cross buns doesn’t mean it’s time for slack capitalisation, particularly when it comes to holidays.
Easter, Good Friday, Easter Sunday, Shrove Tuesday, Pentecost, Christmas, All Soul’s Day, Hallowe’en, Thanksgiving Day, Labour Day, Foundation Day…the list goes on and on and they are all capitalised.
Holidays (religious or otherwise), as well as days of the week, months, names of people and places (countries, rivers, cities, mountains etc), businesses, the pronoun “I” and the first word in a sentence all begin with a capital letter.
Some people think titles of books or movies and headings for articles etc should have all the first letters capitalised (but then leave out words like the, of, in), while the Style manual for authors, editors and printers goes for a simpler approach of just capitalising the first letter. In the end it comes down to personal preference or house style. Consistency is key.
Also, one that often pops up is the capitalisation of seasons (autumn, summer etc). Unless it’s your house style, seasons shouldn’t be capitalised unless there’s an exceptional reason. For example, Autumn colours this season are brown, orange and maroon.
Rule of Thumb
Use capitals for holidays, days, months, proper names, the pronoun “I” and the first word in a sentence.