When I was in middle school, I got the itch to organize events. No, that's inaccurate. I realized the need for organization, so I did it. There wasn't really an itch, just a desire to get to the end goal and no bridges provided to it. The point is, I got started in event creation and project management shortly after I hit the double digits, so I have a little bit of experience in it.
I don't know how to make things successful in terms of large numbers, so if you're reading this for that info you should just go Google it and find a blog or article written by someone with huge events listed under their credentials. Large numbers aren't really my thing, although it may have been early on. What I've learned, instead, is that I want people who want to be part of the experience.
Here's how I got to this place with my events and projects, and some lessons I've learned the hard way that I'd like to impart to you as a shortcut past frustration, disillusionment, and reorientation. Don't worry - you can still go through those feelings in other areas of your life.
I used to invite everyone. Then I realized if the event was for everyone it wouldn't be effective. It would be too general. It would be like seeing a family doctor to remove your gallbladder: She could do some of it, but probably wouldn't go deep and precise enough to ensure maximum impact of the procedure. So I started creating target demographics. If others came from outside those demographics, that was fine; however, I needed to accept I couldn't focus on all people and all their needs and still make something important happen. This allowed me to weigh the feedback I received. For example, if I created a project for high school students and a middle schooler said it wasn't meeting them where they were at, I was able to adjust the value of that critique as it applied to my intention.
I used to count on people to attend who said they would. Then I learned that people love ideas in theory but often beg off when reality sets in. They have to figure out logistics, they have to sacrifice their time, they may have to get uncomfortable. This was one of my key takeaways from Jesus' parable of the banquet: Invite them, but plan for a significant fraction to not follow through. Experience and context of the event in question will allow you to figure out an estimate for yourself, but I tend to use a 25-40% follow-through rate as a rule of thumb for my projects. The more sacrifice/discomfort required for participation, the lower the follow-through rate.
I used to assume I knew what people wanted. Then I started listening to attendees to help me to expand the vision - and often cut off parts of my own. That was humbling but critical, and, like with any kind of good pruning, it led to new growth. I also found out the attendees didn't always know what they wanted, so we discovered it together.
I used to work alone. Then I figured out that I am lacking in a lot of areas. A lot. It's that whole body analogy the Apostle Paul writes about, but this became even more real when I first started attending film festivals, where I witnessed films that were written, directed, and edited by one person. There were so many parts of these films that went too long or in a weird direction, characters who weren't developed enough or had an unnatural amount of focus on them, and other errors or poor decisions that could have been caught by having someone else in just one of those three leadership roles. So I've brought on team members, especially ones who were different from me and could see things and do things I could not.
I used to keep going. I still do. I make strategic plans that get rewritten countless times, but the planning gives me a framework for future forecasts and goal-setting. I fail a lot, I recalibrate a lot, and I am constantly educated by the brutality of experience. I have had to kill off projects I really liked because the potential or people or my own longterm interest just wasn't there. It's not easy. It's not always fun. But I love it because when something truly works I get see the goal reached: The people who want to participate receiving something valuable to them, being part of something that matters to them.
I wish you the best as you create and manage your projects to your own goals, and then allow them to evolve to meet others' needs. I beg of you: Don't worry so much about others' external standards of numbers or volume - define your standards and your goals, then work toward those for real impact.