We used a Trademark Attorney. At first, the Gov't said no to our name but we fought it and won. It cost us about $1000. You can do it yourself for a lot less.
See USPTO listing for "Controversial Pictures".
There is a company named Controversial Records and USPTO said it was too similar because they have DVDs listed under their products. We explained that their DVDs will have music while ours will have feature films. Different product on a similar delivery method. We won.
Also, the USPTO tried to say that our name is "Descriptive" but so are a lot of others.
Did you know that the USPTO office was going to close in the early 1900s because they said that "Everything that can be invented has already been invented"? Our government at work.