Step 1:

Right, this step is nice and easy, you're only just really drawing a rectangle using the typical 2 pixel segment method. Remember to check you're happy with it's dimensions since if you do it too high or slim it could effect how well/bad your house looks.

http://img183.imageshack.us/img183/5004/52886349cw6.png

Step 2:

Ok, this is where we start to break away from the conventional methods of pixel art, this time we going up the left side with the 2 pixel segment method, but once you reach the top and start to go down hill on the right you're only placing one pixel at a time, this is so you get a steeper curve.

http://img80.imageshack.us/img80/619/98077197el4.png

Step 3:

This time you're just echoing Step 2 a couple of times to make your arch look 3D, if you had no problems with step 2 this should be a sinch, but check the picture below to know where to place them.

http://img90.imageshack.us/img90/6607/65914283bm0.png

Step 4:

Once again this is a copy of step 2 and 3 but just on the other side, I'm pretty sure I just copied the layers from 2 and 3 and placed them there and removed the parts that I didn't need. As for the connecting lines they're just two standard lines, by now you shouldn't be finding these a problem at all.

http://img377.imageshack.us/img377/4449/54839349kw7.png

Step 5:

We're going to be doing some work on the top floor now, so draw a line down and across to decide how big you want the top floor to be (I find 60/40 works best). Once this is done you can put in some windows, now these can be as simple as drawing two boxes, but by adding a few more simple lines you can make them look great.

http://img377.imageshack.us/img377/3543/52587595zw5.png

Step 6:

More easy steps! Just a few more lines on the front of the house, we're trying to make this part stick out, if this makes no sense to you scroll down to see final product.

http://img80.imageshack.us/img80/8396/62876085yy0.png

Step 7:

Easy again, draw in a door which is just a box really. Now the roof over the sticking out wall is also simple, going across you have a standard 2 pixel set line, but when we want to go up with the lines we only use one pixel to make it look: / , this makes it look like a dipping steep slant.

http://img510.imageshack.us/img510/6540/27970105xe0.png

Step 8:

Once again another window, this one can be two separate small ones, or a long one, I went for long as I wanted to make it different than the upstairs.

It's all strait lines again.

http://img235.imageshack.us/img235/9706/60050636tc3.png

Step 9:

This step is optional, and to be honest probably the hardest to not mess up. We're putting a chimney on, this means it has to slot on to the top of the roof like: /\ - from a side angle, however since isometric pixel art looks at things from a 45 degree angle it isn't as simple as that. The best thing with this is to start from the top and work down, once you get to the bit that looks like / just try to use a mix of 1 and 2 pixel lines to make it steep, not not too steep. The picture below should help clear what I mean up.

http://img88.imageshack.us/img88/6192/45343716dx7.png

Step 10:

Colour it in, it's pretty big so this takes up most the time, but go for any color, I also cut off a part of the roof on the left side since I didn't like it there. Anyway here's what it should look like when coloured:

http://img440.imageshack.us/img440/989/finci9.png

http://img396.imageshack.us/img396/363/10rd7.png

AND DON'T STOP THERE!

Once you make one, changing the hue on the house gives you another allowing you to make your own little attached houses, add in some grass and a plant or two and it starts to shape up nicely

Have fun, thanks for reading.