When it comes to matters of faith everyone has their own beliefs and fairies are no different. What does tend to be different for fairies is the way faith is treated. In general the fairy approach to religion can be summarized as 'that which is worshiped or revered gains power'. It is in someways the opposite of the common human approach, which can be sometimes be thought of as 'that which is powerful is worshiped or revered'. Of course it's not that cut an dry on either side, but it works as a good general starting point for the difference between common fairy and common human beliefs. For a fairy, religious devotion isn't thought of as much as about 'belief' as it is about 'choice'. To choose to hold something sacred or holy is to invest power into that thing, the more of one's own energy one chooses to devote to something the more power it gains in their eyes. The more power and renown something has, the more it can do and therefor the more useful it is to worship, but this is often a secondary concern and many fairies believe that worship for purely pragmatic reasons is less potent then devoting one's self to something just because they genuinely want to. Fairies do often hold that such purely pragmatic belief is done in 'bad faith'.
Fairies tend to also similarly look down on the idea of religion being some sort of 'duty' or 'obligation'. To most fairies any religious belief that demands worship or devotion is at best poisonous to the ones who follow it and at worse poisonous to everything around them as well. They also tend to be opposed to organized religious institutions (of significant scale at least) and especially opposed to anything they even suspect to be any kind of religious indoctrination by one. In fact fairies tend to shy away from the idea of having any kind of fixed 'canon' of teachings or beliefs, and instead prefer syncretically following whatever they feel fit. Most religious practices are often thought best carried out in private, and mass public displays of worship are often seen as disruptive or suspicious. This doesn't mean religious gatherings or places of worship don't exist, just that fairies rarely are that overt about prayer or other such rituals and preaching is usually kept to a minimum. Fairies tend to find most common human religions and religious practices to be repugnant, dangerous, or at least very very silly (especially Christianity, on witch there are also many historical reasons to bare a grudge), although most will grudgingly accept a person's choice in following one if they show 'true faith' as a fairy recognizes it.
While fairies do often worship many gods and other spirits (as personalized representatives of abstract concepts and as beings in their own right), they aren't necessarily thought of in the general sense as much more then a human might think of famous celebrities. In other words, often awe inspiring and worthy of respect for their power and fame, but not beings beyond understanding or reproach. To a fairy, gods and other spirits are just like any other being, at least in that regard. A fairy might just as well worship another fairy they are a fan of, or even a human in rare cases, living or dead. A fairy wouldn't necessarily see much difference between a fan convention and a temple, a cosplayer or a priest. What matters to a fairy is the devotion and energy put into something, not the exact form that devotion takes. That doesn't mean that that's all fairies worship however. To fairies anything and everything can be a target of worship, from directly worshiping abstract concepts to revering inanimate objects and everything in between. The wonders of nature are a common choice. Fairies often make little shrines of a sort out of things like a refreshing spring or well, a waterfall, a neat cave, a particularly large tree or pleasant grove, a small hill, anywhere that seems like a nice meeting place. Sometimes fairies may put up some altars made from a pile of stones or standing stones marked with runes. There might be entryways marked by Stonehenge-like gates. Sometimes it's just decoration, but sometimes it means a fairy felt the need to protect a place with magic and a barrier will keep out any who don't go through the gate. Sometimes these gates act as portals to other places.
Well loved objects are thought to be in some sense holy as well. Objects with sentimental value are prized and said to hold lots of power. Indeed, magically a well loved object can be very powerful, and can hold many blessings or sometimes powerful curses. An object's history and it's connection to the history of others is very important to many fairies. Though they don't truly exist in the fairy world, museums are also places a fairy might think of like a temple of a sort. One not only holding precious objects for display, but also in charge of understanding and explaining their history. Many fairies tend to be hoarders of artifacts that they personally find important, even if no one else does. It is even not that uncommon for fairies to, rather then revering or worshiping any particular thing, devote one's self to a concept or ideal. To a fairy someone who devote themselves to something like 'justice', 'love', 'science', 'power', or 'pleasure' are simply putting their faith into something like any other personal belief. And of course, many fairies choose to put their faith in only in themselves or sometimes in nothing at all.
Ritual can also be very important to fairies, both magically and spiritually (in fact magic and spirituality are often seen as deeply connected, but not always truly synonymous). Fairy rituals are often personalized or are part of a large collection of haphazard folk beliefs and practices. The form rituals take often doesn't matter as much as the function they serve and the feeling behind them, and fairies mostly encourage experimentation and improvisation over strict traditionalism or sticking to any one set of rules too strictly. This often extends to 'social rituals' such as manners or protocol, especially for solitary fairies (to a point anyway, there are still basic guidelines to follow if one doesn't want to be seen as rude). The exceptions where traditionalism and/or following a set of strict rules is expected are mostly for those within the Seelie courts and occasionally when fairies need to have a formal meeting, trial, or duel.
Since fairies are practically immortal they don't tend to care much about the idea of an afterlife. Many fairies find the idea silly or disdainful, but often acknowledge it's possibility. Most fairies who care to think about such things might say that things can create echos that might linger long after they are gone and leave it at that. Fairies also don't tend to care all that much about the origin or meaning of existence as a whole. There are speculations about it and a few scattered legends, but many fairies would say that how things came to be doesn't really matter, and what things mean is up to every person to decide. If fairies have any generally agreed upon explanation about existence as a whole, it's that existence is about, if anything, existing. That everyone and everything that exists, real or unreal, is fulfilling whatever role it may have for it's own sake and not for the sake of some higher purpose or god. Often fairies believe that happiness is truly found in loving one's own existence for it's own sake. Loving one's own existence doesn't necessarily mean only loving one's self, but also can include the world around them and everything in it. It also doesn't necessarily mean one can never be unsatisfied or upset, just that maybe one shouldn't let negative feelings ruin their passion for existing. And it certainly doesn't necessarily mean one shouldn't ever strive to change themselves or the world around them, just that maybe they should remember and appreciate where they are and what they are doing. Of course most fairies wouldn't say that in so many words, but it's really kind of important to us. After all, when a fairy doesn't care about existing anymore they die for good.
So in the end, to a fairy wonder and passion can be found in all things great and small. All you have to do is look!