Internal 'Discount Booze' sub-branding was placed around stores with signage promoting special offers. The slogan was also added to store fascias.
The initiative was tested in 12 stores and then rolled out across a further 13. Now Smile plans to extend the branding across its whole estate of 96 stores next year.
The retailer is also looking to add to its portfolio of stores and extend its Country Market format.
Last month, Smile opened its second Country Market format in Bruton, Somerset. The concept has greater focus on high-quality locally sourced food.
Chief executive Jeremy Symonds said the company planned to open a third Country Market in February although he declined to say where. "We want to open about 12 new stores of all formats during 2007," he said. "Our emphasis is going to be on finding quality sites in the right location, rather than quantity."