How do I make an entry stay at the top of my journal? What is a sticky entry?

You can create a sticky entry in your personal journal and also in a community as long as you both are the author of the entry and the community's owner or maintainer and it is you.

How to create a sticky entry

To make a sticky entry, check the "Sticky post" box in additional settings of "Tune in and publish" menu when creating or editing an entry. If you are using the old editor, check the "sticky" box at the top of the page.

Any entry can be made sticky by editing it and selecting the option to make it a sticky post, and similary any sticky entry can be converted back into a normal one by removing the checkbox and saving the entry. Sticky entries respect the same settings as normal entries: they can be posted at any privacy level, have tags, use non-default commenting options, etc.

You can only have one sticky entry at a time. If you already have a sticky entry, when you create or edit a new entry, the text for this feature will change to "Replace sticky post". When you have posted or edited an entry and selected the option to replace your sticky post, the previous entry used as a sticky post will become a normal entry, and it will be ordered in your journal based on the date & time the entry was posted.

Scheduled sticky entries

You can also schedule an entry to post at a later date and have it become your sticky entry when it is posted. When the scheduled time & date arrives, the new sticky entry will replace the existing sticky entry.

Further Reading

What order do my entries appear in my journal? How do I exclude entries from RSS feeds and friends pages?