IKEA Mirror Mosaic--Day One

Here's the IKEA mirror, in black. I bought 8 of these yesterday--my first trip to IKEA. What an experience THAT was! Now that I have experience with the "maze," I plan to return and look around a little more.
And here are the 32 "tiles" I cut out of foamboard. Someone had told me that they measured 1 1/2 inches square, so that's how I originally cut them. I measured, drew lines, and scored with my craft knife. And then I went back and evened out some of the edges, since some looked different after I turned them over....After painstakingly cutting them, I laid them out on the mirror and discovered--oh no!--too large. So then I guessed at 1 1/4 inches--and yes, that's the correct amount. So I trimmed every single tile (all 36 that I had originally cut). Actually went kinda fast though--I was so mad at having to redo each tile that my cuts were swift and hard!
So here's how the blank tiles look laid out on the mirror. A little sloppy, but hopefully the finished piece will look a bit more precise in spacing. But this seems to be the correct layout--6 across, 2 on each side. The spacing isn't exact between them all, even when neatly laid out.
THEN--on to deciding my color scheme. I've been into turquoise and lime green for months now, so I decided to go with that, adding various shades of blues and citrons and greens. Went through my stash of "play" papers and auditioned them for the mirror. I had more than enough! No surprise there....

So these are some of those papers, cut down a bit. Now I need to decide whether to cut and then glue, or glue and then cut. I favor the latter, since I'm not real precise in my measurements. Will probably use gel medium. I'll also need to decide how to handle the edges of the "tiles." All this can wait til tomorrow--or perhaps Monday.