For TripAdvisor (NASDAQ:TRIP) shareholders, the past several quarters have been a painful exercises in patience. Each earnings report holds out hope that the company might finally overcome the revenue headwinds created by its instant-booking feature. But so far, a return to the top-line growth rates of yesteryear remains elusive, and the less said about net income -- which fell 39% last year -- the better. With TripAdvisor set to report its first-quarter earnings on May 9, here are the items I'll be watching most closely as I look for any signs that the business is beginning to turn around.

Monthly user growth -- the stronger, the better

TripAdvisor's most important asset is its loyal, engaged, growing user base. For 2016, the company's monthly active visitors averaged 351 million, up 14% year over year. And TripAdvisor's users are busy beavers -- posting 290 pieces of content every minute.

The ocean with palm trees in the foreground

Image source: TripAdvisor 

TripAdvisor needs to grow its monthly users to keep feeding this content machine. The higher the user base, the more ratings, reviews, and content they create -- and the more users TripAdvisor ultimately attracts.

What to look for: For each of the past three years, monthly active visitors have grown at least 16% year over year during the first quarter. If the company can deliver something close to that, it's proof that TripAdvisor's collection of ratings and reviews remains as valuable as ever.

Hotel revenue -- any improvement is positive

The hotel segment is currently responsible for around 80% of TripAdvisor's total revenue. However, it's also the segment struggling the most, as consumers just haven't adopted instant booking -- which allows users to book their stays directly on TripAdvisor -- as quickly as the company had hoped. In 2016, hotel revenue fell for four consecutive quarters and decreased 6% for the year.

There are a handful of reasons for optimism, though. The rate of decline did begin to slow late last year, with hotel revenue falling only 3% in the fourth quarter. Based on recent trends, it looks as if this segment ought to finally break through to positive growth either this quarter or next. And encouragingly, the number of hotel shoppers actually grew 8% last quarter. Finally, TripAdvisor is making substantial investments to educate its users about the benefits and convenience of instant booking in an attempt to increase adoption rates.

What to look for: Even if the company doesn't achieve growth in hotel revenue, any improvement over last quarter's 3% decline means things are still moving in the right direction.

Better mobile monetization rates will be crucial

Roughly half of TripAdvisor's user visits now take place on mobile devices, which makes the company's struggles with instant booking even more problematic. Last year, management stated that mobile users were monetizing at a mere 30% of the rate for desktop users. This troubling statistic was not addressed or updated during the fourth quarter, leading me to believe that the company hadn't seen any marked improvement.

What to look for: Specific updates around the monetization rate for mobile. The percentage of TripAdvisor traffic coming from mobile will only grow larger over time. If the company is going to have a chance at getting back to significant top-line expansion, getting more revenue from its mobile users has to be part of the equation.

While TripAdvisor certainly has its work cut out for it, the company believes it will return to double-digit revenue growth in 2017. If it can do that while continuing to grow its user base and getting more of its mobile users to use instant booking, this could wind up being a very good year for shareholders. That said, if adoption rates don't improve and hotel revenue starts trending the wrong way again, look out below. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.