Calendar Ideas?

My boss told me to set a certain number of meetings per week as a reasonable goal. He told me to wait until after a certain date. Then I got mixed up and scheduled them before the date.

I got confused my an email thread that a bunch of people got added to. Then just said yes to a meeting date forgetting to account for the "after a certain date".

It only negatively effects me but I do want to try and find a solution to not make the same mistake in the future. Typically I find a physical planner works best for me to visualize but I'm having to use the outlook calendar as well to make sure there's no conflicts when other people in my organization try to schedule me for things.

What can I do to better visualize/utilize outlook and still keep everything straight? Anyone use a scheduler like calendly? That integrates well with outlook? Any advice on how to make the outlook calendar work better for me?