How do i prepare serious objection to a planning application from a local paper shop extension?

The Local residents want to object to a planning application made by a corner paper shop who have bought the residential house next door and now want to extend their shop into a mini market,there in a off-licence shop 5 houses from their shop and a local post office mini market 20 houses away,we don't want or need this as it attracts youths already causing anti social behaviour,the corner shop owners have only been here for 3 yrs and they have already been raided by HMS Customs and Excise for selling counterfeit goods and have been visited on a numerous occasions From trading standards regarding allegation's of providing tobacco products to under age children,the shop is dirty and unkempt never painted outside and looks desperate,and is in a well maintained residential area with hard working people who are anxious about their intention,apart from profit as the goods are often over prised or nearly out of date stamped,that sort of thing,I know you need to make a good case for fighting this can anyone suggest the way forward .I live in Lancashire UK