Giving offerings is a common practice. Done for various reasons, to build relationships with deities, to show respect, to get on and to maintain on a good side. If food and liquids are offered, it is generally not to be consumed out of respect. What cannot be consumed tends to be left alone, not taken back, again out of respect.
Incense offerings are often given, and one of the most common offerings given. It is no surprise that I give incense offerings and on a regular basis. Taking time to think, offerings of water, soy milk, various flowers (lavender, kangaroo paw, grevillea, soursob, eucalyptus) and fruits (apple, banana, orange, mandarin) are given.
Maybe variety is a good thing, especially with flowers and fruit. Various tastes and smells to be enjoyed. Flowers also add a nice look to alters even if of offering. The fragrance of flowers is always lovely to be able to smell near alters, gives a relaxing feel.
Reading about what others give as offerings, bread, honey, water and milk seem to be popular offerings to give. Regardless of how often one may read how a certain offering is given by a multitude of people, a good idea or two can be gotten of what to give as an offering. It helps, even if slightly.