The earlier response that said that costs before a property are placed in service can't be deducted anywhere is incorrect. Costs before a rental property is placed in service can be added to the cost basis of the property that you depreciate. You can just add the costs to the building cost basis, or enter them as a separate depreciation item. The start date of the depreciation would be the placed in service date.
The costs that you can add to the depreciation basis include mortgage interest and real estate taxes while you were getting it ready to be rented, travel expenses to go work on the property, utilities, pest control, and regular maintenance costs.
If anyone wants tax code references for this, see § 263 and § 1.263(a)-2(d).
A side note, certain costs may also be optionally deducted in the current year as § 195 startup expenses, but that's a complex topic and I would mostly not recommend that option for people doing their own taxes.
