Chris brings up a cool point that I use a lot. I often don't group things one after another. I will often use channels 1-100 for dimmers, 101-200 for LEDs, 201-300 for one type of movers, 301-400 for another type, 401-500 for a yet another type, and 501-512 for misc stuff like strobes and foggers. I often likewise have more then one universe at my disposal, so this changes from universe to universe. I have also never used every single channel out of the 512 available on one universe. Always less channels needed or I have more then one universe and split the groupings to make DMX runs easier.
The nice part about doing it this way is each fixture starts at xx1, so they add logically. If I have 4 DS575Es at 24 channels a piece, a tech can ask me what address I want the 'third' one and I can instantly say, "273" without even really having to think or look at paper work/my console.
The point is do what works for you, be it lining channels on after another or a method like I use. you might use something similar, a combination, or completely different. Find something easy and simple for you to use and stick with it to make all your shows easier.