It's worth trying different things - from soil (loam tastes way different to peat!) to sniffing your way around a planted english-style garden (to get references for things like sweet pea, honeysuckle etc). Buy the fruit you haven't tried from a greengrocer or supermarket, in case it crops up in your coffee. And always taste new things with the idea that you have or haven't got a label for it, to reinforce it where you have or are creating one. Eg. That's a blood orange, that's a chinotto orange, that's a Iyokan, that's a Satsuma, then through Tangerine, Tangelo, Navel orange, etc so you learn to differentiate. In the same way cupping a heap of coffees from different origins reveals a heap about each because of the comparative characteristics alongside the standalone ones, tasting all food (and drink) with the aim of storing descriptors will help you use them for coffee. And drink lots of different single origin coffees from lots of different roasters. Most blends will be Choc/Caramel/Carob/Toffee/Nuts, possibly plus a bit of fruit (usually not tropical ones). Getting out of a habit of drinking mostly the same or similar tasting coffees will also help.
