I think it depends on what you mean by “managing”. I’ve worked for a long time in a space that requires management of multiple projects simultaneously, as many as 25-30. The most important thing is to keep a constantly updated status report and have full timelines through completion for each project, and calanderize everything. Ideally have all of these things in 1 document for all projects.

Start every day with a “hot sheet” either for yourself or with your team to quickly align on what needs to happen today and the next couple of days, make sure you’ve got resources aligned appropriately, and then execute. Planning your time carefully is going to be key - so work on A from 9-10, B from 10-11, 15 min break, then incorporate boss’s comments to A from 11:15-11:30. PM tools are very helpful but you can do this with simple tools you already have - your Outlook/Google calendar, old-school to-do lists, and a timer. All of this planning takes time, but is well worth it.

Couple of key tips: if you are doing this as part of a team, or are relying on others to do pieces (eg, for Art to layout a piece), let them know well in advance what is needed and when they can expect to receive it, and when you’ll need it back. Be honest with yourself about how long things will take - don’t plan a 1h task to get done in 15 min. And DO block your calendar to avoid meetings, calls, and other disruptions. If there are meetings you can’t miss, factor that in. Lastly…you can usually change timelines if you do so far enough in advance. Don’t plan to have a major milestone on multiple projects on the same day unless you are very confident it can actually happen.