It's kind of cheating, I know, but it's often really helpful to copy the arrangement of a track you like. Once you've done this a few times you'll start to get a good idea of what kind of stuff works well in the various styles of music you like.

It's also worth noting that Techno more than any other kind of dance music seems to have a licence to be truly free-form in structure.

For example, with stuff like Breaks (my other favourite), most tracks have an intro... a 1st sequence... a breakdown... a big drop followed by a main sequence... another breakdown... then one more massive drop followed by ramming the whole thing home with a final sequence and then an outro. Obviously this is just a general case, but it's a forumla I often follow quite a lot to reasonable effect. (i.e. You can break all the rules, but sometimes you'll end up with tracks which don't work quite so well on the dancefloor, or which DJ's will avoid like the plague).

With Techno there's much fewer rules about how tracks are arranged. Some build and build, some bring elements in and out over time, some evolve slowly etc. Just about everything is fair game - though in my experience certain stuff works better in certain styles.