In the long run - and, if you are a struggling exporter, that can be a very long time - exchange rates reflect long-term actual economic fundamentals: things to do with the underlying competitiveness of our economy and its firms. If our productivity performance outstrips that of other countries, our exchange rate will tend to rise.
If our inflation rate is consistently higher than those of other countries, our nominal exchange rate will tend to fall. And so on. But that is for the long run. In the shorter-term it is largely a matter of making sense of fluctuations in the demand for funds and in the willingness of the world’s savers and investors to supply them.