It might sound like a strange place to start, but in order to think clearly about what light your space needs, you really need to have thoroughly understood how the space will work. For example; where will people be within the space, and what will they do there? Lighting an area where people are generally passing through will need a different treatment to somewhere that people spend extended periods of time. Of course, if people will be working there for any significant time you need to provide decent light levels and avoid harsh contrasts.
Apart from the ergonomic aspects, it is really important that the three dimensional shape of the space has been well understood. For example, if a space is overlooked by a landing or mezzanine, then you will need to be careful there are no direct views into the top of the up-lights.