I purchased a second home in December, and closed on the 30th. I'd like to write-off the applicable closing costs, but I will not receive a 1098. How do I?

[xmasbaby0]

Is the second home for your personal use?   Sorry---closing costs on a home are not deductible.

Buying a home is not a guarantee of a big refund.  Your deductions for homeownership combined with your other deductions (if any) must exceed your standard deduction to change your tax due or refund. If you purchased your home late in the year, you do not even have a full year of home ownership deductions.

Your closing costs on your new home are not deductible except for prepaid interest, prepaid property tax or loan origination fees.  There are no deductions for appraisal, inspections, title searches, settlement fees. etc.

Your down payment is not deductible.

Your homeowners insurance for fire, hazard, flood, etc. is not deductible for your own home.

Home improvements, repairs, maintenance, etc. for your own home are not deductible.  (With possible exceptions for certain energy credits) (BUT——do make sure you keep careful written records/invoices, etc.  of any improvements you make to the home for someday when you sell it.)

Homeowners Association  (HOA) fees for your own home are not deductible.

[NCperson]

@sidneyd37 

<< except for prepaid interest, prepaid property tax or loan origination fees>>

you can use the amounts listed on the closing statement provided by the closing agent (attorney, etc.) ; it will not be provided on a 1099 by the loan servicer. 

[Opus 17]

You should have received a closing statement from the agent or your attorney.  The only deductible items will be property taxes and mortgage interest.  You should have paid 2 days of interest (or maybe 1 day). You can enter that as interest and check the box for "I did not receive a 1098".  

You paid the seller a credit for property taxes for the time you would be owning the house, if taxes are paid in advance in your area.  For example, in some locations in New York State, county property taxes are due Feb 15 for a Jan 1-Dec 31 tax year, and school taxes are due in October for a September 1-August 31 tax year.   So in that case, you would have paid the seller a credit for 1 day of county taxes and 8 months of school taxes.  You can deduct those taxes as if you paid them directly to the taxing authority.

Some other closing costs can be added to your cost basis, which may reduce your capital gains when you sell, but are not immediately deductible.  Other closing costs have no tax treatment at all, not adjustments and not deductible.  This is discussed in publication 523.

https://www.irs.gov/forms-pubs/about-publication-523