Conference organizing comes with many challenges. Attendees are going to complain about the food. Someone is going to think "There aren't enough SEO/Security/Regular Expression/". Overall, you are not going to be able to make everyone happy. But one way to increase attendee hapiness and make sure people walk away with solid lessons is by curating mini tracks.
Your job as an organizer is to curate the experience and lessons you want your attendees to have. You shouldn't pick a talk because it's popular, you should pick talks that tell the story you are aiming to tell. The story you are telling is one that takes its characters and lessons from the speakers and talks you choose.
What will the attendees be talking about tomorrow?
The attendees of a conference are going to go back to work, are going to rejoin their professional circles, and bring things with them. Unless you are doing longer workshops, these are going to often be the themes and lessons that are weaved throughout the day. I like to create "mini tracks" of a couple of talks that build upon a theme.
For example at a WordCamp, a mini track on "Fundamentals of WordPress Development" could include talks on custom post types, child themes, the user and role APIs and post meta. These talks may be at multiple levels, but that's ok. They all build upon a thesis of "WordPress has multiple ways to be extended". A new to development person may gain an understanding of how a plugin they use works and may come up with a new idea. A new to WordPress developer may gain an understanding of how to structure a custom plugin. An experienced WordPress developer may gain a new way of thinking about when to use one API over an other.
Some themes come in different styles than others. I've seen a number of different types of mini tracks including ones focused on a vertical ( Real Estate, Education, Enterprise, etc ), those focused on a type of worker ( Freelancer, Manager of People, Remote Worker, etc ), or on more generalized theme (Advancing as a Developer, Redesigning Websites, Social Media).
Mini Tracks in Action
Mini tracks were something I first observed for a conference at WordCamp Boston 2011. This conference went so far as to print the names of these tracks on the schedule. (Sidenote: The greatest technical talk I've ever seen at a WordCamp was at this WordCamp. )
By grouping three "Enterprise" talks together, an attendee who wanted to gain an understanding about enterprise could make sure they were setup in one location to do so. And while there, they could learn about growing teams, growing code bases, and growing sites. With Boston having so many world class universities, the education track was a natural choice. This track included engineering talks, strategy talks, and more. It was about a common interest, rather than common skill that united these talks.
Another example can be found at WordCamp DC 2017 were three talks in a row looked at questions concerning equality, inclusion, and intersectionality in three very different ways. Attendees could see these three talks and walk away inspired and with a better understanding of how they could use WordPress in an entirely different way.
If you start working on a conference schedule, consider what the lessons are that you want the attendees to walk away with. Think about the themes in the talks. Schedule something "Hard" or "Complex" or "Technical" where it might not be obvious. Allow people to learn something they weren't ready to learn. Give them something to walk away with that may not be useful for years, but might stick with them.