The world out there is waiting for you to explore it! Travelling, and trying out new things, is the best way to understand.
I have travelled a fair share myself (visited 60+ countries), and am currently back in my home country, Germany (having lived overseas for several years).
I love old and old-fashioned things - this is one of the reasons why I always have a stack of postcards or aerogrammes to send, calming down for an hour or two, with a hot (or cold, depending on the season) beverage, to write down my latest thoughts.
Also, food is one of my favourite topics - I try everything. Maybe you can share and tell me, what was the strangest food you ever tried? ("Strange" is a very relative term. When I tell my Asian friends that raw, minced pork is a delicacy in Germany, they frown. And my German folks do not understand why I love Durian...) I love all those food-themed cards postcrossers sent already - but you are the sender, and I trust you make the best choice for a nice postcard, with whatever picture.
Be creative! I trust you will send me a nice card which you would also like to receive.
...and I would love to have an airmail etiquette on the card you send!