Did you know that next to Valentine's Day, Mother's Day is one of the busiest days for restaurants? The National Restaurant Association (NRN) estimates that 80 million adults will treat out their loved one at a restaurant this upcoming holiday. In fact, NRN projects that Mother's Day 2013 will produce stronger restaurant sales versus last year.Across the nation, restaurants are aggressively attracting consumers by offering Mother's Day brunch and dinners specials. In such a competitive environment, how does a restaurant stand out among an ocean of others?OpenTable, the popular online reservations system company, recently produced a guide that reveals top 25 Mom-friendly dining cities in the U.S.Rounding out the top 10 cities are:Long Beach, CaliforniaTampa, FloridaBoulder, ColoradoDallas, TexasAustin, TexasColumbus, OhioRaleigh, North CarolinaHouston, TexasCharlotte, North CarolinaLas Vegas, NevadaSo what exactly are the criteria that makes these locations so great for a Mother's Day celebration?OpenTable explains:The results are spread across 16 states and point to the places where it's terrific to be both a mom and a foodie. In order to provide this ranking, the OpenTable Mom-friendly Dining Index was calculated using four variables based on OpenTable reservation and diner reviews data from 2012: the percentage of people who dined out for Mother's Day; the percentage of restaurants rated "kid-friendly;" the percentage of restaurants rated "romantic;" and the percentage of restaurants rated "hot spots."To view the rest of the top ranked cities, read the entire OpenTable release here.