In most traditional restaurants in Athens you will be presented with an extensive menu, often in both Greek and English, which lists a vast array of seasonal dishes. Items currently available will have the price written beside them.
Some of the best most authentic tavernas will not even have a menu on display but in these eateries you simply go into the kitchen or to the grill to see what looks and smells most enticing, and then make your choice.
This is probably the best way to familiarise yourself with Greek dishes if you are unsure of what to order.
I'd like a/an/some...: Tha
aubergine (eggplant): melitzana
ice cream: pagoto
roasted or grilled: psito
chick peas: revithya