When I suggested space invaders, I didn't really think things would get so out of hand. It started as a suggestion for a painted bathroom wall decal which then turned into possible bathroom art which eventually turned into office art because I actually managed to make the darn thing too large. Finally, I think I am going to look into a professional, artistic space invaders poster for the future. There are a few really nice ones on Etsy that I've got my eye on.
In the meantime, this project didn't turn out half bad. I really like this little character looking at us from the one previously blank wall in the office. So I suppose the purpose of this endeavor was still maintained because now the office feels a little more finished.
Anyway pixel art is probably the most simple art you could ever create. Being artistically inclined is not necessary at all.
The size of your picture will depend greatly on the size of your "pixels" or in this case, square pieces of paper. At first, I was using 2" squares, but finally reduced them to 1 1/2" squares since the finished invader was too big at that size and I thought the 1/2" square was a little too small (though, it probably would have worked out all right in hindsight).
Depending on what pixel creature you're creating, cut out a bazillion squares accordingly. I searched for space invaders online and found a picture that already had the pixels well mapped out, but it's not really that difficult to figure it out on your own. The space invader as seen above required 46 squares.
If you want a less formal design, may I suggest post-it notes? I'm sure you've seen the elaborate pixel creations made using individual post-its around the web. They're cute and fun when stuck onto windows and walls.
Then I loosely arranged them into my invader starting with the longest row in the middle and building out from there. That way I could adjust where I wanted him on the poster paper.
I marked out where I wanted him to start and end and drew really faint lines for each line of pixels so I'd have some sort of guideline towards keeping the squares straight. That's probably the most frustrating part of the whole thing. Keeping them straight (and some of them just won't be straight. Let yourself relax on account of human error).
Finally, glue the whole mess down. Naturally, this was exactly the moment I ran out of glue, so I had to use mod podge which worked just as well.