One thing that has gotten quite popular in Minecraft is to create the character you are playing yourself or that others plays into a statue in Minecraft made out of cubic blocks. This is all possible because the skins are just as well as the world made out of pixelated cubes. Here I will show you one way to do it. It's an easy way and the way I usually do it whenever I'm asked to do it for a friend. Just follow my simple steps and you will be soon there!
First off start by going to a skin website and get a skin of your liking. If you are new to building things in Minecraft it's suggested that you choose a skin with less details as that will ease the process of creating the skin in-game.
Once you have found a skin which you like and would like to turn into a statue you should copy the image you see on the skin page to Photoshop, Gimp or any other image editing program (see example below). I will use Photoshop in my example below but you could just as well do the same things in Gimp which is for free. Resize the skin to its doubled size (in this case 400x800px)
Step 1: Find the Pixels
As all skins are pixelated it's easy to find each pixel. Look at whole the skin and see what pixels in the skin you will replace with what blocks. You don't have to decide all pixels right now but at least get an idea of which blocks you are going to use for the pixels used in the skin image. If you are not familiar with what's a pixel then please have a look at the red small square.
Step 2: Start Building
Use the image of the skin in your editor as a blueprint. Print it out on a piece of paper if you like. Hopefully when you are done you will have something along the lines of the image below. Best of luck to you!