Step One: What is the assessor's estimate of the market value of your property?
You'll find this information on the assessment roll.
Step Two: Develop an estimate of the market value of your property
Homeowners can learn how to estimate the market value of your home, whereas other property owners may wish to contact an appraiser or other real estate professional. Generally, if the assessor's estimate of the market value of your property reflects roughly the amount for which you could sell your property, then your assessment is fair. http://www.tax.ny.gov/pubs_and_bulls/orpts/mv_estimates.htm
Step Three: If your assessment is too high
Often, an informal discussion between a taxpayer and an assessor can result in a sharing of information beneficial to both parties. If such a discussion does not result in a reduction in your assessment, and you still feel as though your assessment is too high, you may wish to contest your assessment.
If you are assessed fairly, but you feel that your taxes are too high~
Assessors do NOT determine your property taxes. If you feel as though your assessment accurately reflects the market value of your property, but you still feel that your property taxes are too high, you may wish to address this matter with the taxing jurisdictions that impose taxes in your community - school board, county legislature, city council, town board, fire district and other special districts.
The assessor cannot assist you with tax matters, but only with matters pertaining to the assessed value of your property.