This is Alister Wang in Taiwan (Republic of China). I have been a stamp/cover/card-collector for 20 years. My preferneces of cards are:
1. universities in your nation. (my favorite)
2. featured buildings in the city you live.
3. natural scenes in your country.
If you can also use pre-stamped postcard, ATM stamps, personalized stamps, some unusual stamps or recently-issued stamps as the postage, that would be wonderful. Thank you very much.