I find that the things most likely to be mistranscribed, either by the enumerator or when it was put in the database, are the surname and the age. Ages of children, though, are likely to be more accurate than those of adults.
First names tend to be well transcribed, though middle names are often missing altogether.
Even when a person was trying to hide, they rarely lied about their place of birth, so that's a good thing to search on even though unusual places of birth may have caused problems. Don't forget that wildcards can help here. Families who moved around, though, often forgot which children were born where.
Both Ancestry and FindMyPast allow you to look for other people in the household, so mentioning someone you expect to be living in the same house increases your chances.
The surname variants in my one-name study are very prone to mistranscription, even when the person concerned was literate, so I use every option I can to locate someone missing from a census.
Assuming someone is on their own, and having failed with the full name and age +/- 5 years, I start by removing the date of birth. Then mess with the place of birth - use just the county if the township gives nothing.
Use wildcards to help. Ancestry has more options than FindMyPast here. I can use formats like D??BA*, where FindMyPast just allows an asterisk at the right hand end.
When someone has been consistent with a place of birth in other censuses, try just the first name and the township. You may end up scanning through 20 pages of results, but usually you can spot a likely mistranscription.
There will always be cases which we are unable to find for some reason. If someone was just a lodger, they may not even have been asked the proper spelling of their name, or where they came from.
On more than one occasion I have seen the place of birth dittoed all the way down the sheet, and the the enumerator has realised that one person part way down was actually born in foreign parts, so changed just that one line. When the transcription was done, we end up (correctly) with results he never expected. Great great uncle Henry's whole family is down as being born in China rather than Wigan.
