You can use any light copic friendly ink. I use Distress Ink. Mainly because it's the only ink line that I have many colours of. I used the images from the Sweet Smiles set.
Tip 1 : I stamped the machine off to the side to create some kind of dimension even though everything is more or less one layer except for the sentiment. I really like doing this especially for one layer card.
Tip 2 : The great thing about no-line colouring is, you don't have to trouble yourself and create a mask. If you can see it in the image above, some of the balls overlaps. But because you will not see the line in the end result, this doesn't matter :)
I hope you like this card as much as I did :)