Living World
If you do Living World, the most likely case study is the desert in a poor part of the world because it has never come up before. Last year, the whole focus of the question was on deciduous woodland so don't focus your revision too much in that direction
Restless Earth - last year the case study was on a volcanic eruption so this year it will probably on earthquakes in poor and rich parts of the world.
Water on the Land - meanders have never come up so learn them inside out and how a meander may result in an ox-bow lake.