The Yes side's arguments must also focus on less positive areas such as the consequences of a No vote, which would result in Scotland being "thrown into despair" and could lead to Holyrood's wings being clipped.
Speaking at a fringe meeting during the SNP's conference, he said: "If this referendum fails, it will fail on the basis that people put their British identity ahead of their Scottish identity. So, therefore, when we look at what we are going to do in the final stages, we have got to go into attack on the British identity.
"We cannot allow ourselves to be complacent, to stand back and hope that things will come our way."
Mr Wilson told delegates at the Law Society of Scotland fringe event that there are several areas where the campaign for independence needs to make an impact, such as the north-south divide and the consequences of a No vote.
"It's not all that positive but it has to be done," he said.
"What will happen if Scotland votes No? For those who are in the No camp thinking their future is safe and secure, forget it.
"I only wish we were as half as intelligent as the Downing Street Mafia in some ways, and as tough as the English, because Scotland has been taken to the cleaners.
"If Scotland votes No, our clout will disappear, we will be thrown into despair. And any promises that we get for devo max? Forget it."
Mr Wilson said Scots law would be diminished by a No vote, with the country's unique legal system being assimilated to that of England, while "the wings of the Scottish Parliament are likely to be clipped".
His comments follow the publication in August of his critical analysis of the Yes campaign in which he said there is "absence of vision, passion and emotion".
Also appearing at the Law Society event, Professor John Curtice of Strathclyde University agreed that the question of British identity is important in the debate.
"Feeling Scottish is a source of consensus in this society. The problem from your perspective is, at the moment, it is how British people feel that is more clearly related to whether they are for or against independence than how Scottish they feel," he said.
The Yes campaign needs to win arguments on the economy, defence and foreign affairs, and "why the United Kingdom is bad for Scotland", Prof Curtice said.
"You have to persuade people that, systematically, the Union is not in Scotland's interests, not some particular Government," he said.