The SNP looks increasingly likely to make an attempt to form the first minority Scottish government.
They have been holding power-sharing talks with the Greens, but a coalition would only give them 49 MSPs, short of the 65 needed for a Holyrood majority.
The anti-independence Scottish Liberal Democrats have turned down the prospect of an SNP power-sharing agreement.
The Nationalists emerged as the largest party in the Scottish election with 47 seats, beating Scottish Labour by one.
Talks between the SNP and the Scottish Green Party, which has two MSPs, have been on-going, although there are still several issues to be resolved.
SNP leader Alex Salmond, who has expressed a preference for coalition government, told the BBC: "The bulk of our preparations now is perhaps assuming the responsibility of government as a minority.
"That's where we are focussing most of our attention at the present moment."
The Greens may back the Nationalists over a "confidence and supply system", where they would support Mr Salmond to be first minister and his party's budget, while dealing with other issues on a case-by-case basis.
Speaking after the discussions with the Greens broke up for the day, Mr Salmond said: "There is still a bit of talking to be done. There aren't any sticking points, we're just looking at the range of ways the parties can co-operate in Scotland's interests."
Green co-leader Robin Harper said he would have to refer back to his party's council.
"We will need further discussions on transport and other aspects of our policy differences before we come to a conclusion," he said.
"We are working very positively towards that at the moment."
A first minister has to be appointed within 28 days of the election
Mr Salmond, who described confidence and supply as a "perfectly workable model", earlier suggested a minority administration could operate through building consensus with other parliamentary parties.
Prospects of a coalition with the Lib Dems faltered after leader Nicol Stephen said the fundamental stumbling block to a power-sharing deal was the Nationalists' demand for a referendum on independence.
The Lib Dems have also ruled out a deal with Labour, their former Scottish Executive coalition partners.
The election for the 129 member Scottish Parliament also gave the Scottish Conservatives 17 seats, the Lib Dems 16 and saw the re-election of Independent Margo MacDonald.
Meanwhile, Conservative MSP Alex Fergusson has ruled himself out of the contest to be the next presiding officer at Holyrood, following speculation that he might be nominated to replace George Reid.
It is thought the Tories feel one of the larger parties - particularly Labour - should fill the post, which is also being considered by Margo MacDonald.
More than 100,000 ballots were counted as spoiled in the election and in one seat - Cunninghame North - former Labour minister Allan Wilson is considering a legal challenge after losing by 48 votes.
A lawyer is also preparing to contest the outcome of the Glasgow region.