So I was watching a great little webseries called "Every Frame a Painting". It breaks down a lot about film and it's many varied aspects. On the most recent one he showed a clip from a show called Stand-in. In it the creators of South Park surprised some kids at NYU their first day of class.
Now regardless of what you might think of the show or the guys who make it, they know their shit or they would have died penniless and hopped up on heroin in an alley way long ago. It's worth a watch.
Why am I telling you all of this? It's because there is this one section I want you to pay particular attention to. It's about structuring a story. The advice they give very much can apply to routining a magic act. A routine is/can be a story. Maybe not in a traditional fairytale sense, but it should have a beginning, middle, and end or, if you want, a start, a build, and an ending.
Being able to write a proper routine is like crafting comedy. It's a skill unto itself completely apart from the mechanics required to work the props. You can have all of the magic you want but if it doesn't flow or make some semblance of sense, then the act can suffer.
Therefore, you should watch the clips above...