Whether registering prior to election day at the municipal clerk's office, with an SRD, or even on election day, nearly all Wisconsin voters must now provide proof of residency to register. 

Always Useful Proof of Residency
League Pamphlet, Making It Clear is a tool for community members helping citizens navigate requirements for registering and voting in Wisconsin. It clarifies many of the ambiguities surrounding proof of residence and voter photo IDs.
Making It Clear
The League of Women Voters has prepared a helpful explanation on the proof of residency rules when registering to vote.
Proof of Residency Guide
The Government Accountability Board explains 
Military and Overseas Voters
Proof of Residency can often be looked up online. Here is a handy list of websites:
Proof of Residency
Libraries in Dane County are a great place to potentially register new voters.
Libraries in Dane County - Register to Vote
If the voter has a Public Library card: LINKcat may be used for Proof of Residence
Registering UW students presents some unique challenges. Here are Tips – Registering to Vote for UW-Madison Students