I can answer this question from the aspecting professional Social Media Managers.
Our agency calls out clients once a month, to plan the month ahead.
We take into account trending topics, any relevant holiday that the account can tag along with the trend, and any major holiday, if they feel they want us to produce content for that (usually not, unless collated branded content).
We also talk about promotions, polls, and relatable content production, that produces better engagement.
If boosting is involved, we discuss the target, and the purpose of the boost.
We also recommend that clients continue to post their own in-person, in-house content such as photos, anecdotes, stories about events that occurred in the store, and anything that shows personality of the business.
Depending if the client has strategic outreach, or strategic follows, we discuss possible targets for the month.
Then, we go ahead and set our post calendar, and creative calendar, and copy calendar, based upon the content required.
If that’s how agencies do it, that should be a pretty good guide for any individual doing the same thing.
And contrary to popular belief, we don’t post daily, as this is an example of a branding campaign, daily posts without boosts or relevant ads without a lot of nurturing the algorithm, don’t get much penetration without paid ads.
Personal brand and personal posters, may have more time for this. Agencies are rarely involved in this type of campaign, due to the cost.