Hey there,
I'm going through this too, but we didn't end up with a loss. I'm not 100% on how to do this anyway, but I'll give you my understanding. First, if you are not already, make sure you are splitting the expenses between personal and rental use. For example, if you rent only one room, calculate the percentage of the house that is rented. So, if you have a 1500 sq. ft house and a 10x15 room for rent, you are renting 10% of the house, and can deduct 10% of the interest and property taxes (and a few other things) from your rental income, but the remaining 90% would be deducted as usual from gross income as itemized deductions. If you are renting at a very cheap price (less than market rate), you may not be able to deduct any expenses against rental income.