This is the very first origami model I learned, you can even turn it into a fish with a swift cut to its back. This is my sixth instructable, and, now that I have my hands on some much needed glue, I shall soon be doing projects not origami related (Yuss!). If you are a beginner, or know a n00b who could use this information, this is the perfect project for you. Tell me what you think (And if you want to know how to make the fish) -- and PLEASE check out my origami eagle. That instructable has been mystreriously neglected by my fellow instructabrarians.
Step 1: Triangles and something less threatening than tribulations
Start with the colored side down, though you are best achieving your model with a sticky note or a big newspaper. Fold one of the corners to the other, giving you a neat isosceles triangle. Fold the corners farthest from each other to meet the top tip, or meet in the center.
Step 2: Horns
Rotate the model 180 degrees. Fold the top layers up to meet the upper corner, then fold those back down to the edge they create (i.e. the crease). Fold those back up once again to meet the other edge of themselves. Refer to the picture for more clarity.
Step 3: Shape taking
The lowest corner will go up to the horns we just made -- DO NOT let it touch the top corner. There is no proper measurement for this, but make sure there is plenty of room below it. Fold the remaining excess paper up as far as it can go. Then fold the back flap up to the top corner.