Here is a simple little card I made a year or so ago and sold on eBay. It is so easy to make. You can find other ideas like it close at hand. First I found a coloring book with simple images, took it to a copier and reduced the image of the crab until I had it at the size I needed for this card. Next I cut it out and traced around the edges onto a colorful piece of paper; I used a bright red. I outlined each part of the crab with a black pen, like Pilot Varsity Extra Fine. Any smooth writing pen will do just fine. There is a minimum of shading done with brown chalk and a Q-Tip.
The background was done with six layers of cardstock. Three are sand and three are water. The top of each row of sand is smudged a bit with brown chalk and the waves are all cut free form and inked a bit with the black pen. To get uniform pieces for the eyes and eyebrows, I used little throw away pieces left after cutting out letters with QuicKutz Sunshine Font. Also used the font to say "Whassup ?". A few grains of sand penned in finished up this lil ole crab.
Hope you try one too. If you do let me know. I would love to hear from you.