That's kind of an overly broad question, without a specific example of what you're trying to do...
Most countries (at least on real-life Earth) don't have the size to contain a huge variety of geographical features.
If you're trying to expand a country into an entire planet, the most simplistic thing to do is simply scale up everything - a stream becomes the Amazon River, a pond becomes one of the Great Lakes, a sinkhole becomes the Grand Canyon, a stand of trees is now a primeval forest and hills become mountain ranges...
But that's largely most useful for expanding a country into a continent.
If you want to wrap it around a planet, consider dividing the country up into its different geographical elements (or some representative concept thereof) and then think of it as sort of an exploded view drawing, turning each one of them into a continent - lakes become oceans, maybe part of the plains and the forest is now a continent like Africa (divided between huge areas of grasslands and jungle), maybe the coastal region becomes an island chain, etc.
Probably the first thing you'd want to do is figure out just what about that particular country you're trying to represent, and whether you want to try to replicate those things physically, or just the feel/the idea/the concept of them.
For example, a desert is, at it's essence, just an empty space, or a lack of other things. In many ways, an ocean could represent the same thing - from a certain perspective, the void of outer space is a desert (or an ocean) because there's nothing there...
