One of the best tips I can give you is simply - "spelling don't count". Yep you heard me correctly. Time and time again I've heard, "that can't be my family the name isn't spelled the way my grandmother always said it was spelled".
While I can appreciate grandma's attention to detail and wanting the family name spelled what she believed was the correct way, I also understand the logistics of having a German talking to a Swede, or an Italian, or vice versa.
Working for Mr. Brown Eyes in the tax business that we own, I've come to understand more clearly the census takers issues. We have alot of different ethnic backgrounds coming to our service and when they call, try as I may, the name gets spelled the way I hear it. Often times its not close to what ends up on the tax return. Luckily for me they don't see how badly I can scramble their names. Its not intentional, but it does happen. I'm sure the census takers in the early years had the same issues.
When you think of the situations when the census taker was in the field, perhaps it was raining, storming, snowing or who knows what else. Maybe the couple he was interviewing had 10 kids all of them running around wanting attention. Perhaps the couple was reluctant to give information so you got what you got. Who knows?
Whatever the reasons, no matter how badly butchered, spelling don't count! So keep that in mind next time you are searching for your ancestors on the census or in other records.