When a sale of real property is ordered to be made at private sale, notice of the same must be published in a legal newspaper of the county in which the estate is being administered, once a week for at least two successive weeks before the day on or after which the sale is to be made, in which the lands and tenements to be sold must be described with common certainty: PROVIDED, That where real property is located in a county other than the county in which the estate is being administered, publication shall also be made in a legal newspaper of that county. The notice must state the day on or after which the sale will be made and the place where offers or bids will be received. The day last referred to must be at least fifteen days from the first publication of notice and the sale must not be made before that day, but if made, must be made within twelve months thereafter. The bids or offers must be in writing, and may be left at the place designated in the notice or delivered to the personal representative personally, or may be filed in the office of the clerk of the court to which the return of sale must be made, at any time after the first publication of the notice and before the making of the sale. If it be shown that it will be for the best interest of the estate the court or judge may, by an order, shorten the time of notice, which shall not, however, be less than one week, and may provide that the sale may be made on or after a day less than fifteen, but not less than eight days from the first publication of the notice of sale, and the sale may be made to correspond with such order.