The only good events are those made specifically to benefit the attendees of the event, not for the sponsors, not for the organizers.
There are many different formats for having a good event, there are lots of basic things that are important to get right. All of those things can seem intimidating, for good reason. It takes a special type of person to get all of the details of an event right.
That said, the events that I have enjoyed the most are the ones that I know were built solely for the benefit of the attendees.
This has been a tricky insight for me to get. Every event starts out as one to benefit the attendees. The issue is that at some point as an organizer, you need money: Finding a space to host the event, providing food, providing infrastructure. All of these things require money and once money is involved, you have to make a compromise somewhere to get that money.
The typical compromise that an event will make to get money is to get sponsors. Sadly, the traditional model for sponsorship is one that will insidiously shift the focus of the event from one that is built to benefit the attendees, to one that is built to benefit the sponsors.
To run an event that doesn't suck, you have to make the event for the benefit of the attendees.