I've been working on this for ages and after having to revise it over and over again I think I 'm finished, well I'd rather not add anything else to it.
lots of issues with this...
First of all there's a white pixel in the top section of the image. Then: wow... 234 colours?! That's a lot of colours... You could reduce it to about 36 colours and use a better contrast level; that would help you in creating better details. As for general composition, the piece looks a bit empty (considering usual elements crowded iso).
Imho you should start with a basic pixel art friendly software (for example graphicsgale), a little canvas (maybe 200x200 px) and 20 to 30 colours. But don't lose heart, iso is not so easy as it seems... You've done a nice first iso: now go on and improve :D