So how do we section Colossians in an effective way? First, I would begin in Colossians 1 and just read (or skim) through the book, trying to find logical or topical breaks. Most Bibles have headings that separate verses into big topical sections.
Make of list of the verses for each section and add a topic or heading of your own. (Example: Colossians 1:3-12 Paul's Prayer) Try not to have verses that overlap between sections; use our large segments as an initial guide! (Example: Doctrinal headings and sections for Colossians 1:3-2:23)
As for our Overview sheet, I follow Kay Arthur's blocking method (on her At A Glance sheets).*
As you can see, there is ample room for the chapter themes (and key verses), but to the side, there is space for segments or section divisions. There is no reason why each section needs to correspond by chapter; often chapters mark new topics, but that is not always the case.
I just drew a similar rectangle on my Overview sheet with a small column for sections. (It doesn't need to be very small; make it big enough for you to write inside it!) I listed our large segment divisions from our Overview (intro, doctrine, praxis, closing).
To the left, I added a second column for sections! Here is my final list of sections for the book of Colossians:
Prayer for Colosse (1:3-12)
Jesus Above All (1:13-20)
Complete in Jesus and his Gospel (1:21-29)
Paul's Struggle and Warnings (2:1-8)
Christ's Work (2:9-15)
Why Live as the World? (2:16-23)
Keep Seeking Above (3:1-4)
Put Aside Sin (3:5-11)
Let Christ Rule... (3:12-17)
...in All Areas (3:18-4:1)
Prayer and Wise Conduct (4:2-6)
We are going to take Sectioning a step farther and begin working on Paragraph Themes. These themes will help us develop an outline of Colossians.
*This image was taken from my personal copy of Kay Arthur's Philippians/Colossians Study titled That I May Know Him.