Scotland's First Minister has called on the UK Government to negotiate a Brexit deal that "limits the damage as much as possible."
Nicola Sturgeon said that Prime Minister Theresa May should agree to a transition period inside the single market and customs union.
Writing in The Guardian she also said that transition must not just be a two-year postponement of "falling over a Brexit cliff edge".
Ms Sturgeon called on the EU and UK Government to confirm citizens' rights even if talks in the next 10 days fail to progress sufficiently to move on to trade negotiations.
The First Minister said that following US President Donald Trump's "completely unacceptable" retweets of anti-Muslim videos posted by Britain First, Mrs May must accept the "enormous folly" of hoping that a trade deal with the US could replace the trade, jobs and investment lost by taking Britain out of the EU single market and the customs union.
She said it is time to banish language that "characterises the EU as our enemy" and approach the next phase of talks in a spirit of co-operation and solidarity.
Ms Sturgeon remains "firmly opposed" to Britain leaving the EU, describing Brexit as a "monumental act of social, economic and diplomatic harm", adding: "But if Brexit is to happen, then it must happen in a way that limits the damage as much as possible".
She said that decisions so far have been taken in the interests of "appeasing Tory Brexiter backbenchers" but said that it is now time for the economy to come first.
European Council president Donald Tusk has given Mrs May until Monday to come forward with an improved offer on the terms of the UK's withdrawal, including the "divorce bill" and future citizens' rights, as well as the Irish border, if there is to be progress at the December summit.
In her article Ms Sturgeon wrote: "The prime minister needs to come away from the EU summit with a clear agreement to move into trade talks and a clear statement that transition will mean remaining in the single market and the customs union - nothing less.
"Warm words and cryptic soundbites will not suffice when companies are beginning to make real decisions that will impact on people's jobs. And that transition must not be simply a two year postponement of falling over a Brexit cliff edge. It is an opportunity to recognise a better way forward."
She said that in the new year the Scottish Government will publish updated analysis that sets out the benefits of the single market, and the impact of choosing not to be in the single market.
The First Minister wrote: "While it isn't perfect, the single market protects workers and environmental rights; allows us to work, study, and live in other countries; brings investment; and at a stroke solves the challenges on the island of Ireland. It is without a doubt still, after all these months, the best way forward.
"Scotland did not vote to leave the EU. The decision is one that many in Scotland have not reconciled ourselves to, and cannot. As we head into another year of Brexit talks, it's time to banish the language that characterises the EU as our enemy, and instead approach the next phase of talks in a spirit of cooperation and solidarity of benefit to us all."