The question is: What is it, that you want your map to show?
It is obvious that this is a political map due to the different colors you used for the countries (?).
On what do you focus? The landmass itself, countries, political structures, should it illustrate a certain background story?
There is a vast amount of things you could add depending on the purpose.
Somewhere here is a quite good list made by Ascension called something like "Things to put on a map".
Maybe you should have glance on this piece ;-)
(EDIT: I found it. Here it is, thanks to Ascension)