You should use specific language. That is special clichés, syntactic constructions, etc; in other words, your language should be stylistically marked and diverse.
Apart from this, your geography dissertation should have a logical and consecutive structure. You are to show the ability to think rationally and reasonably.
You also con provide some tables if you have made some calculations or you want to present some statistics. It will not spoil your geography dissertation , but only improve your position;
Do not forget to resort to only up-to-date materials.
Ultimately, check the text of your geography dissertation to the last word once again before handing it in.