You can do a generic "to any present", if you're not feeling a specific call to take notice of. Many Asatru bloats end with a release of any wights that may have been inadvertently trapped by their hallowing, and many different paths share "cakes & ale" with any present by returning it to the Earth at the end of the ritual. If none were present, well, you've just made friends with the raccoons, too! When heading to new territory, I will often take something with me as an offering. If I have food and water, then libation. Or it might be incense ash- I save the ash from incense burned during rituals and spells, and use it for other spells- or in this case, as a fragrant tribute to cast to the compass points, or to a natural feature that is obviously inhabited.
In your own yard, you can install a Kamidana or a spirit house or arch; if there's a well or spring you might make a clootie tree. You can also put a shrine or lararium of some kind in your house to be the focus of attention.Nothing need be elaborate; it's the respect and good will that matter.
peace,
ES