This part of the process requires you come to the realization that many, if not all, third-party modules that you used to create your site are not available for D6.10 because the developer stopped working on it OR it got integrated into D6. It is also the time to clean up. The objective for this process is to convert your site into a D4.6.8 default site. Below are the steps I did to clean up my site for the transition from D4.6.8 to D6.10.
Nodes: Go through all your nodes and delete all the nodes you don't need to keep.