It seems like a daunting task, attempting to find family members that were lost years ago, especially when some states have closed adoption records. But,  it is possible…

Write Down Everything You Know About the Adoption
Take the time to really think about everything you know about the birth and adoption of the one you are seeking. No detail is too small or insignificant.  Talk to your own parents or other family members who were involved in the surrender of your child.  Ask them for whatever information they may have.

Contact the Agency that Handled Your Adoption
The agency that handled your adoption may be able to provide you with information and search help although it may charge a fee for these services.

Apply for Your Non-identifying Information
According to the Child Welfare Information Gateway, nearly all states allow people who have adopted and adult adoptee's to access information about the parents who surrendered the child.  California, Idaho, Nevada, and New Jersey allow access to adoptive parents only. However, only about 28 states allow parents who lost a child to adoption to non-identifying information about their child or the people who adopted their child.

Accessing this information, if possible, is very important in attempting to find family members. Knowing the occupation of a natural parent at the time of adoption may seem a small thing, but this small detail may be the lead needed to bring about an adoption reunion.
 www.childwelfare.gov/systemwide/laws_policies/statutes/infoaccessap.cfm

Register with Your State Registry
The Child Welfare Information Gateway states that many states utilize a mutual consent registry. This means that both the adoptee and the birth family must register whether or not they are interested in an adoption reunion. Learn more about your state's adoption registry. The White Oak Foundation website contains information on the type of registries in each state.
http://www.whiteoakfoundation.org/mappage.htm

Register with The International Soundex Reunion Registry (ISRR)
The International Soundex Reunion Registry (ISRR) was developed with the idea of providing a means for families that have been separated due to divorce, adoption, or foster care to reunite. ISRR is a mutual consent adoption search registry, each adult (18 and over) has to have registered with ISRR in order for a match to be made.
http://www.isrr.net / It's free!

Check All Registries Monthly
Check registries on a regular basis, and if you find a possible contact try the contact information a number of times over the next year.

Read about Adoption and Seek Support Groups for Those Trying to Find Family Separated by Adoption
It's important to know that you are not alone, and to connect with others who understand your need to find your birth family.