There is good advice coming on this front from Nonprofit Vote by Sarah Blahovec:

The disability community is one of the largest groups of voters in the United States. In 2016, 16 million people with disabilities participated in the election. However, voter turnout of people with disabilities is still below the rest of the population. There are still many barriers that exist for voters with disabilities throughout the process of registration, voter education, and casting a ballot.

One of the largest obstacles for the disability community is outdated ideas around who is disabled and what they can do, and this is a challenging attitude in the voting space as well. However, with some simple strategies, you can ensure that your voter registration activities are inclusive of the disability community.

See full list here.