Quick answer
Choose whether you want today's date, a month grid or your next appointment, then pick the smallest widget that displays that information clearly. An event widget needs the right calendar source and may require permission; a date-only widget usually does not. Put the next useful action where you will notice it and test with an ordinary event before building an elaborate theme.
Decide what your home screen should answer
A calendar-first layout works best when it answers a clear question: What is next? You do not need to show the entire month, a habit dashboard, two clocks and every app on the same page. Start with the next event or the current day's agenda.
Choose whether you need a list of upcoming events or a month grid. An agenda makes the next commitment obvious. A month grid is useful for orientation but can become difficult to read in a small widget. Pick one as the main feature and treat everything else as supporting information.
Give the calendar the strongest position
Place the calendar near the upper or middle part of the screen where you naturally look first. Leave room for a few essential app icons and a clear clock if the calendar does not already include time information. Keep the surrounding wallpaper quiet enough for the event text to remain readable.
If the agenda is clipping, enlarge the widget or reduce the amount of text it tries to show. Moving it to a different home-screen page may give it the height it needs. For size decisions, see 2×2, 4×2 and 4×4 widget planning.
Make sure it displays the right information
A good-looking calendar widget is not useful if the selected account or calendar is wrong. Open the provider app and choose which calendar is shown. Confirm that events appear there before judging the widget. On an Android phone, a calendar widget may require access to calendar data, but each app's implementation is different.
If the widget has no events, determine whether the day is actually empty, the wrong calendar is selected, or the app lacks access. Our guide to calendar widgets showing no events walks through those cases.
Leave space for action, not decoration
A practical first page could contain a clock, one agenda widget and four frequently used apps. The exact positions depend on launcher grid size, hand reach and your habits. Keep the shortcuts you act on most often nearby and put less-used widgets on a separate page.
Review the layout after using it for several days. If you keep opening the calendar app because the widget hides the next meeting, increase its size or simplify its display. If you rarely read a decorative card, remove it and give your attention back to the agenda.
For broad placement instructions, start with adding an Android widget and adapt the steps to your launcher.