I think evilyoshi has no idea where to start with pixeling but is very interested in it and came here for advice.
So here are a few things to help get you started:
Start by poking around these links. Read some of those tutorials, it is a great way to start.
Tools & Tutorials:
http://www.wayofthepixel.net/pixelation/index.php?topic=3467.0Top Threads with interesting advice and discussions on pixeling:
http://www.wayofthepixel.net/pixelation/index.php?topic=4912.0-If you want to make a 'retro' looking zombie, start by using a smaller canvas, something like 16x16 pixels.
-Look at reference photos. There are tons of pictures of zombies on the internet. Most of them are going to be very detailed so try squinting and blurring out all the details to just look at the general shape of the zombie. What do you notice and how is this different from what you have made?
-Practice drawing in real life. You must learn to think visually(proportion, color relation, shadowing) if you want be good at pixel art. Drawing and painting are great ways of practicing this. Try drawing things from real life, DO NOT draw from memory. People who can draw from memory are people who have spent years studying how to draw from real life.
Tips on this attempt:
-Save the file as a .png or .gif and post that. Do not post screenshots.
-The head is gigantic it looks more like a dinosaur than a zombie.
-The eyeball is gigantic, probably because it is trying to fill up some of that big head. But in real life eyeballs are pretty tiny when compared to a head.
-The body is three heads tall. I am not sure if this is intentional or not. But be aware that realistically a human/zombie is about 7 heads tall.-
There is much more that I could go on about with this but it is not going to be very nice and it is not worth it until you take a look at some of those tutorials and try them out.
You are brand new at trying this so don't worry about not knowing how to do things. Just explore and have fun.