I used A6 watercolour such as this and drew a gentle line down the middle, using a ruler, where the crease would later be made to turn it into a card. I used half of the paper for my illustration. In this instance it was all about fishing vouchers for the family, so I set to it armed with a wikipedia's Brown Trout page for inspiration. :p I very roughly sketched out the shape in pencil, mostly to get the proportions right and then I cheated a little by using black ink to create an outline and add some detail.
However, to be honest there's not so much detail on a fish, so launched in with the colours pretty swiftly! I must admit to being a little free and easy with the colour interpretations of the so-called 'brown' trout. But who wants a card with a brown fish on the front??! ;) I didn't want to feel restricted by the black lines, that just makes it all a bit cautious. So I took relish in going outside the lines, quite liberating in fact!
I tried a couple of different perspectives and even got a bit adventurous and branched out from the brown trout to something a bit more exotic!
What do you think? Why not give watercolours a whirl? Anything goes and the more interpretive the better! And if at first you don't succeed, try try and try again! (Practice really does make perfect with these bad boys!!)