Special services are typically those where the occasion governs the selection of texts, liturgies, homilies, and prayers.
This includes but is not limited to child dedications, baptisms, weddings, Holy communion services, and funerals. These can occur anywhere one likes, but are usually performed in church or in one's home.
I find that using a Minister's Manual is a good way to organize my thoughts. I use the Nazarene Manual, Christian Minister's Manual, and Book of Common Prayer.