so here's how i went about building my paint station for my hobby. i find it saves space and after a couple of months you get used to where every colout is.
a note on the Styrofoam before we begin, it has to be thick enough to raise the paints up so that you can see which pant is which. 5mm or 10 MM wont do it, i recommend at least 20 mm.
so to start, take a paint and messure how much width you need to cut for the paint to sit comfortably on the foam.
(sorry pics a bit dark, but you should get the idea.)
use a strait edge and a sharp utility knife to cut the strips you will need.
repeat till you have enough tiers.
at this point i like to put a row of paints on and then count up how many rows i will need, don't worry if you get to few rows you can always add more. or if you have to many i use em for bits and such.
now that you have the rows, its time to take some toothpicks and start putting the whole thing together, start with the bottom 2 rows and messure how much of a toothpick you will need and cut it to length with whatever (knife, cutters etc, just be carefull when cutting and i guess it should go without saying that you should do all this on a surface that isn't your wife's hardwood floors or expensive kitchen tiles.)
pin the Styrofoam in place, but be sure to pin it well back from where the paints will sit...
repeat till its finished.
make sure it fits, and put the paints on.
and that's how i built this for a work center.