I just finished finding a family in the 1940 census where the surname was very badly indexed. Maybe this will help others-especially those who are not very experienced.
I knew the birth date and birth location and had located this same family in the same county/state through the US City Directory so I knew they were there.
After trying different approaches using surname including soundex and/or given name-I left off the names entirely. I used the State & County-birth date with in 2 years, gender and birth location. I got nearly 5,000 responses at that time. I went through the alphabet until I got to the first letter of the surname and then started down the list watching closely for any matches until I finally found the family I was looking for. Then I entered a correction which maybe sometime will allow others to find the family using the correct surname. I thought others might benefit from this type of approach.