Bullet Journaling Tips

Start new custom collections with a mission statement to stay focused on what's important. Five whys is a great exercise to help get to the root of what really needs to be accomplished. It also helps avoid "junk drawer" collections that ultimately serve no purpose.
Don't depend on colors or fancy artwork lest your system fall apart when you can't find the right color pens or left your stencils in the office.
"Word wrap" at two blocks (when using a dot journal) to prevent words running off of the page and to provide a little extra margin for later addendum/correction.
Write-out your schedule each day to see it at-a-glance.
Keep a "family" collection with a list of medical conditions (e.g. allergies) for each family member, for use in emergencies.
Create a list of key accomplishments at the end of each month as part of the migration process. This is particularly helpful when preparing for performance reviews at work.

Broader Topics Related to Bullet Journaling Tips & Advice

A method of to organize schedules, reminders, task lists, and brainstorming with into a single notebook