With the Earth and Sky mixes, I usually prefer to mix them offline (Ableton,) and I limit myself to an hour, and this usually results in a linear energy progression. With Infinite Horizons I open up the set time to, usually, an hour and a half, I mix live, and I just mix in what feels right at the moment, and almost whatever (trance, progressive house, breaks) can make it into these sets if it feels right. With this one I usually think about what I should play first all week… 😛
As for themes, I always try to express “stories” in my mixes, and I usually do E&S offline so that I can really think about how to make the tracks compliment one another and how to tell a story throughout the set. For example, with Earth and Sky 004 I went for a somber and reflective tone through the first part of the mix with Tuvan and Leo, and then the mood starts to brighten up with A Cry To The Moon and Slave. With Infinite Horizons, it’s harder to really express a story because I usually do it live, but I’ve had good results by just going through tunes that felt right at the moment. All in all, I always try to go for some kind of theme in my mixes. Some of the time you can see how the themes I try to go for influence the covers of the mixes and how they have influenced my choice in show name selection. 🙂