Although promotions will undoubtedly play a role in back-to-school sales, it's not all about which retailers are delivering the best deals.
As children and teens have a growing influence on purchases during the second-largest retail season of the year, experts said stores that offer the latest trends will position themselves to win the dogfight over market share.
"Retailers should start to pay more attention to the purchasing power children have nowadays," said Dave Richards, managing director of Accenture's global retail practice. "Children know what they want, and a portion of the increase in spending that we're seeing can certainly stem from them making just as many decisions for back-to-school shopping as their parents do."
According to Erin Rechner, kidswear editor at trend forecasting firm WGSN, a few themes have started to emerge. One is the prevalence of '90s street sport looks, which include grunge plaids and a darker color palette with metallic. Rechner said this trend is particularly well-merchandised at teen retailer American Eagle and fast-fashion store Forever 21.
Music festival styles, made popular through social media, also will be a mainstay among the tween set. The influence is worked into the layered looks and fringe offered by stores such as PacSun, which carries an exclusive line by Kardashian family members Kendall and Kylie Jenner, Rechner said.
"[It's] that laid back, kind of West Coast vibe," she said.
Skinny jeans continue to be the must-have silhouette for girls and are growing in popularity for boys. Retailers such as PacSun and Express are also gambling on jogger pants for boys, though the trend hasn't yet taken off, Stifel Nicolaus analyst Richard Jaffe said.
Among the younger set, licensed backpacks, lunch boxes and T-shirts are expected to be big sellers, Rechner said. These include Disney's "Frozen," carried at big-box stores such as Wal-Mart and Target, "Angry Birds," Lego characters, "Monster High" and the Disney princesses.
Flash-sale site Zulilly, which carries boys and girls wear, said camo, galaxy-themed prints and London-influenced jackets are also among the top trends.
According to the National Retail Federation, department and discount stores are expected to capture the biggest share from back-to-school shoppers. But specialty stores are expected to see a boost, with nearly 54 percent of shoppers planning to visit a clothing store—up 2 percentage points from 2013.
Jaffe predicts Old Navy will continue to be a winner, as it's been able to balance trend-right product with low prices. In June, the nameplate's same-store sales increased 7 percent, on top of a 13 percent gain the prior year. Other retailers that appear well-positioned are teen retailer Zumiez, which offers a limited assortment of active lifestyle brands; Kohl's, which has invested heavily in juniors merchandising talent; and Macy's, which has brought in vendors such as Sunglass Hut and Finish Line, Jaffe said.
As for the struggling teen set, Jaffe said Abercrombie & Fitch's assortment is looking more "encouraging." Citi analyst Oliver Chen agreed the product, which is less logo-heavy, looks better—but he cautioned the new offerings may take time to resonate with teens, who are flocking to fast-fashion brands such as H&M and Zara.
"Risks remain to restoring positive comps given [an] aggressive promotional environment, fast-fashion threat and uncertainty if Abercrombie & Fitch can reignite as universally 'cool' again," Chen wrote in a recent note to investors.
Urban Outfitters has likewise lost some traction with millennials, having failed to deliver on its reputation for unique products, Jaffe said. Now under new creative direction, he's hopeful that Urban will regain its identity in the second half. According to Chen, it's carrying differentiated fabrics and looks creative, but the assortment "remains a work in progress."
As for the other teen retailers, Aéropostale is trying to become more relevant with its target customer, including a partnership with YouTube star Bethany Mota. To highlight this shift, the retailer's website has been running with the tagline, "You've changed, so we've changed."
American Eagle's strong focus as a denim destination has Jaffe nervous, he said. Denim purveyors VF Corp and J Brand expressed weakness in the segment in their most recent earnings reports, as consumers' interest in activewear and dresses has pulled spending from the category.
A few footwear trends are also expected to steal some wallet share. Rechner said she expects Deckers' new I Heart Ugg line, which targets girls ages 9 to 13, to be popular, while basketball footwear will likely continue to be a top seller for boys.
And with the expected launches of the latest iPhone and Samsung Galaxy, technology and tech accessories will also capture consumers' dollars, Jaffe said.
"That's a scary thing for apparel retailers," he said.
Another issue that should concern retailers: the weak spring season offered no visibility into which trends will resonate this fall, Jaffe said. When spring sales are strong, it's easy for retailers to see which styles the early adopters are snatching up. But because spring selling never really took off, it leaves a lot of guesswork.
What's worse, if no must-have item emerges, it'll be challenging to get shoppers to pay full price, Chen said.
"Kids won't do without, they will buy new clothes," Jaffe said. "It's going to be a challenge who gets that market share."
—By CNBC's Krystina Gustafson