Monthly Spreads
When something goes wrong in bullet journaling, monthly spreads is the most common culprit. Not always — some problems live elsewhere — but checking monthly spreads first will solve a clear majority of the everyday hiccups a beginner runs into. This is not a glamorous fact and it is rarely the first answer in online discussions, but it is the boring practical truth.
So: when in doubt, look at monthly spreads. When the result is off, when the process feels harder than it should, when something has stopped working that used to work — start with monthly spreads. Even when the answer turns out to be elsewhere, the diagnostic habit of checking monthly spreads first is worth building.
That is the short version. Bullet Journaling rewards patience more than cleverness, and almost all of the visible improvement in the first year comes from showing up regularly rather than from any single decision about gear, method, or collections. Most of what is on this site assumes the same thing: that you intend to keep at it, and that you would rather be quietly competent in two years than dramatically excited for two months.