I don’t know if there any best way to do this, but with regard to Steinberg products, I summarized this in a post some time ago: VST Cloud?
If you’re not planning on any form of collaboration on projects, i.e. if you’re the only one working on your projects, then it’s simply a file synchronization issue, however some users have reported problems with using things like OneDrive. It may not be the best approach to have your Cubase project files being synced in the background by other processes.
You could just adopt the simple solution of zipping up your project each time you finish and uploading it to DropBox or copying it into your OneDrive folder.