One practice I use in my career college classroom that has helped me meeet the needs of all my students, perhaps especially those with disabilities, has been to ask all students to write me a letter during our very first class meeting.  In the letter, I ask students to tell me anything I might need to know to help them be successful in our course.  I have had many students tell me "I have dyslexia" or "I had an IEP in high school"; this cues me in to a need for scaffolding and support for which I might not otherwise have been aware.  In addition, the policy in my school is that, understandably, a student must have documentation of a disability or need in order to receive accommodations, and without that documentation I cannot offer accommodations to individual students.  However, I can structure the class so that the entire class can have the option of hearing a quiz read out loud--this is often beneficial for English Language Learners and auditory learners--or have graphic organizers available that can help anyone access the material.