Kimberly Powell at About.com lists some very good tips for searching Census records in Top 10 Search Tips for Census Success. My favorite tip is the last one in her list:

Leave out the name entirely. When all else fails, and the search engine offers enough other options, forego the name and search by other known facts. Searching for someone living in Wilson County, NC, in 1850 who was born in Virginia in 1789 will narrow down the field considerably. Sometimes this is the only way you'll find those people whose names were seriously mangled during the indexing process. Searching by first name only, along with other identifying information such as date and place of birth, can also turn up possibile matches for women who have married.

I describe in detail how this particular method worked for me in performing a particular tricky search in "Brick Walls & Puzzle Pieces".