Bloo is oversimplifying things more than a little (you can use larger brushes to sketch out forms before refining, and any iso artist will tell you the line tool is invaluable, to name a few), but both he and Josiah are correct in that you must have control over every individual pixel, so this light in the corner is not pixel art (NPA). It also seems you've saved as a jpg at some point, as the image quality is ruined.
There is a non-pixeled light effect and it's saved in jpeg format. Make sure to save in png or gif, and never use any effects from photoshop. Pixelart should be done entirely by hand.
Want to give some dough back to all those amazing pixel artists? Donations provide prize money for contests, help cover hosting costs and support new initiatives.
