Now that you have a side business, you probably have a lot of stuff to do, some one time and some recurring. You likely are getting more correspondence and have a mixture of tasks that require both a ton of concentration and no concentration at all.
One No Meeting Day: I have one day a week I spend in my email or give myself time to do projects that are more in-depth
Asana.com: Project management system to track tasks, who is doing them, and documenting information that has to do with a project
Daily Accountability Calls: My coworking space has a virtual membership and having to tell people the things I am dreading doing (and having them ask me the next day) has worked well for me! Before this, I had a weekly accountability call (and still do) with my now friend Ashley who I have still never met in real life but we got matched up sixish years ago when we were both in the same online business group.
Power Hour/Mindless 60 Minutes: Use an extra hour of work in the day and see what work you can eek out (like a bunch of dumb tasks). Can be a good warm-up at the beginning of the day or a good end of the day thing.