As a parent of a student with many disabilities, none of which are visible, this issue was a challenge. Finally, in eighth grade, my son asked me to speak to his classes as he did not want to speak himself but felt the students needed the information. In elementary school, a district person presented the information about Tourette's but never identified him. Now, he wanted students to know. Because I was a middle school teacher, I wanted to help the students understand without criticizing their behavior. So, we did demonstrations. They had to write the pledge of allegiance while I continually interrupted them describing what was happening around them much as an Attention Deficit Hyperactivity Disorder student would hear everything at the same level. Then, I had them write two sentences with their names and describing their families while I interrupted them with instructions to touch their nose or ankle or erase everything they had written because of one error, much like Obsessive Compulsive Disorder does. In both cases, they could not write or finish the simple tasks before them. Then I had them imagine they were stepping in cow manure which elicited groans, and then I explained that for my son, someone spitting felt the same way because of his sensory issues. The room exploded with questions, I answered them all, and from then on, life for him was a bit easier. I would not recommend having a parent do this at grade 8, but a teacher could do demonstrations for the student with their consent. It's a tricky line to walk, but I found that students were much more understanding IF they were given information to understand the WHY something was happening. I know rules prohibit giving out medical information, but understanding with compassion was far better than no information. Find a way to demonstrate without crossing the HIPPA line and help all the students understand the issues.
The most important thing in preparing general education students for inclusion of special education students is rules. Students must understand, up front, what the expected behaviors are in the classroom. One rule which must be a part of any classroom is respect. If a student chooses to disrespect another student, consequences must be faced.
Other practices I have either seen or implemented myself follow.
-Have the student with disabilities introduce himself or herself to the class. Sometimes, this introduction can be important because it allows the student with disabilities to fully explain his or her disability. This can be especially helpful with students with Tourette's (so that he or she can explain verbal or physical tics).
-Speak with the class about expectations prior to the student with disabilities entering. This way, the student does not feel singled out or embarrassed. Remember, nothing specific can be said about the student's medical background. This would break HIPPA (the medical privacy act) rights.
-Ask for a volunteer to help the student with disabilities. Even better, rotate general education students with the student with disabilities. This allows each student to get to know the student on a more personal level.
While these are things which I have seen or heard worked, it does not mean they will work in every classroom. This is really a time of trial and error. The only thing which must not falter is the repercussions for acting inappropriately toward the student with disabilities.