ok, so, you'll notice that my background is NOT clean or minimal, but i didn't cheat, i swear! i made that fun harlequin background from two shades of purple cardstock. it was a little bit of a fussy process, but here are the basics:
trim two coordinating panels of 4.25 x 5.5' cardstock, and mark the BACK of one of them with an evenly spaced pattern of diagonal triangles. i did this by drawing a big diagonal "X" that connected the two sets of corners; then placed my 1" ruler against each line and kept marking until the grid covered the page.
using repositionable adhesive, attach the piece of cardstock with the grid to your other coordinating piece cardstock. trim the double-thick panel along each line (i like a guillotine trimmer for this) until the entire grid is cut apart into separate pieces. it will really REALLY help if you put each segment back into place on your work table (as pictured) when you disconnect them, so that you'll know which piece fits where.
step three... times two:
since you will have two pieces of each segment (one of each color of cardstock) you might as well build TWO backgrounds at the same time. starting with the two biggest pieces from the bottom row, glue them into position on a 4.25 x 5.5" piece of scrap cardstock (don't worry what color it is, it won't show!) it *seems* like the most important thing to get straight and even are the edges, but actually, it's the interior diamonds. you need to make the diagonals line up, so that the next row of diamonds will fit without overlapping and without gaps in between. it helps to apply adhesive to the scrap cardstock, dry-fit the diamonds, then press down each row firmly. at the end, the edges may be a little wonky, so plan on trimming up about 1/8" around each side to make it neat. this will give you a finished two-toned harlequin panel measuring 4 x 5.25".
step four and beyond:
place the finished panel inside your favorite embossing folder and run it through your die-cutting machine. sand the raised parts of the design if desired, or highlight with ink and/or glitter. add ribbons, diecuts, doilies, florals, decorative stitching... or... ALL OF THE ABOVE! mount the embellished panel to a folded card and glow with pride! :)