To attract tourists online, hotel owners should start by providing plenty of photos of the rooms, lobby and facade, according to a study conducted by TripAdvisor.

Among the factors most likely to engage potential hotel guests on a TripAdvisor.com page, photos top the list. And the more images there are, the higher the likelihood travellers will remain on the page to find out more about the property. In fact, TripAdvisor points out that hotel and B&B pages with photos receive 138 percent more engagement from the website's users.

Even more encouragingly, the number of reservation requests made through these illustrated pages was 225 percent higher than for those without photos.

TripAdvisor users also tend to be drawn in by a high number of reviews, as this factor ranks second in determining online engagement. Here once again, more reviews tends to mean that users stay on the page for longer. Of course, it's all the better when the reviews are positive and have been published within the past 12 months.

Furthermore, travellers seem to appreciate when the hotel's management responds to reviews, whether negative or positive. The number of responses from the hotel over the past 12 months is listed as a decisive factor in engaging TripAdvisor users.

In fact, the website reports that hotels having responded to one or more reviews see 17 percent more engagement than properties where the management remains silent. An added advantage is that responding to reviews seems to have a positive impact on overall ratings. TripAdvisor points out that property pages with a 0 percent response rate have an average rating of 3.81/5, while those with a response rate of 65 percent or more have an average rating of 4.15.

For the study, TripAdvisor analyzed data from a selection of hotels and B&Bs in the 25 cities that received the most comments on the website (including London, Rome, Paris) from July 7 to August 7, 2014.