What comes to mind when you think of holiday shopping? Perhaps it conjures up images of braving mall crowds to score a deal at your favorite store or coming home to find a pile of boxes on your doorstep. Whatever it is, it's unlikely that you thought of simply talking to a device.

While it's not quite as quaint as walking down a snow-covered street with shopping bags in tow, using Alexa, Siri, Google Assistant and other voice assistants is becoming an increasingly common way to shop. About one in five surveyed Gen Xers and millennials plan to use these assistants as part of their shopping process this holiday season.

Voice-activated speakers, such as Amazon Echo and Google Home, and voice assistants integrated into phones are rapidly emerging as a new, critical touch point for consumers to engage with brands along the increasingly complex customer journey. For example, they may do a voice search for a new sweater, add the sweater to their shopping cart online and ultimately purchase the sweater in-store using rewards points. While the technology powering smart speakers and voice assistants is still maturing, it could soon experience a watershed moment, not unlike that of mobile shopping, as more people add voice-activated speakers to their holiday wish lists and increase their usage of voice commands on mobile phones.

Although voice interfaces have been adopted faster than nearly any other technology in recent memory, many advertisers are still playing catch-up. As the ecosystem takes shape, however, it's expected to command $19 billion in ad spending globally by 2022. Here are three essential things to keep in mind as marketers continue to incorporate voice into their strategies for the holiday season and beyond:

Maintain trust

Although consumers are rapidly embracing voice technology as a new way to shop, challenges with stickiness remain. The current experience is still a work in progress due to limitations in deep learning algorithms that inform voice recognition and natural language processing capabilities of the devices. Consequently, about half of consumers don't trust their voice assistant to correctly interpret and process their orders or feel comfortable securely sending payment through voice. Those concerns will likely fade over time as the technology advances and people grow more comfortable with the devices — think of how people eventually overcame uncertainty around using credit cards online.

A tougher nut to crack will be those who see voice assistants as a privacy risk and "listening in" on them. Marketers will need to tread carefully and cater to consumer preferences in a privacy-conscious manner. Research shows that the vast majority of people are open to listening to ads through their voice assistant if they can say a "skip" command for ads they don't like, for example. At a time of heightened privacy concerns, giving consumers choice and control will be critical for marketers to build trust on this emerging touch point.

Find ways to surprise and delight

With voice assistants and smart speakers, the omnichannel consumer has become increasingly complex. In order to gain trust and favorability with this audience, it is imperative that marketers dial into consumer preferences and experiences across channels and devices.

For instance, some people may have a strong negative reaction to voice advertisements. Therefore, marketers should recognize this and look for opportunities beyond commerce and "hard sells." Consider taking a page from Tide's book. The brand provides voice instructions on how to remove over 200 types of stains, adding value to the customer experience as they're likely occupied working to remove a stain. Building a single layer of audience identity across a marketing stack will help brands accumulate insights needed to deliver the right voice-driven experience to each consumer.

Make loyalty foundational

Right now, consumers tend to use voice commands as part of their overall brand discovery process, while typically opting to make final purchases online or in stores. In other words, they're not really acting or reacting on voice search results alone. This is due in part to barriers like difficulties in explaining complicated items and executing complex commands like comparing prices.

I use the word "discovery" loosely here, because many people are more comfortable using voice assistants to shop for brands they already know and love. As many of these devices lack displays — which is particularly relevant when you consider shopping experiences — it can actually hamper the discovery of new products or brands.

As such, voice is currently better suited for engaging loyal customers versus acquiring new ones. Forward-thinking brands like Dunkin' — which allows loyalty members to place mobile orders using only their voice — demonstrate how to use this technology to add value to the customer experience. As voice assistants become more sophisticated, marketers will be able to tackle more advanced use cases in turn.

We're still in the very early days of voice engagement, but rapid consumer adoption and technology advancements will give marketers a compelling reason to get in on the game sooner rather than later. Preparing for this future today during the busy holiday season will allow you to master engagement on a valuable touch point long before competitors.