Again, succinct is the rule.
The difference between meditations and personal experience is, of course, length. You can't say as much in 200 words so every word must count. Although devotionals don't have to be personal experiences, they need to be personal. That is, you can write about a verse in the Bible that took on meaning or a simple sentence your child said that gave you insight into life.
Devotionals aren't sermons on paper, lectures, essays, and certainly not authoritarian explanations about how to live. Instead, the short meditations enable readers to connect their lives with God or to find encouragement in their struggles.
Think of meditations as jump-starts for the day (or a way to end the day).