Taxable income. How do rentals help taxes?

[Robert Omoto]

First off, I realize nobody here is going to give CPA services for free.  I am attempting get an idea of my taxes and found I am positive on my rental properties.  So I am wondering how real estate produces a negative taxable income or if i am missing something.  Here are the estimate nnumbers.

Income: 15900

Interest: 5500

Property tax: 3200

Insurance 1000

Depreciation: 4000

Other expenses: 0

Total: 13700

taxable: 2200

Understandably, other years will have maintenance and other expenses, however not 2700/years worth.  How would cashflow producing real estate ever decrease taxable income?