Take Notes and Backup!

Taking good notes and backing up your database frequently is very important, especially if the migration is going to take a long time to perform.

Write down each thing you do, what pages you remove, what items you clean up, somewhere so you can document your processes.

Also be sure to take frequent backups / transaction log backups of your database. If you mess something up (which happens to the best of us) then rolling back to a nearby backup can save you having to redo multiple operations.