Educating a child with special needs is an enormous topic -- worthy of several books -- but we'll cover the basics here today.
The Most Important Part of Special Education
By far, without any question, is realizing there's a problem and defining the problem. If a child makes it to kindergarten without anyone noticing anything dramatically wrong, it's easy to assume the problem is something minor. (Sometimes, it actually is -- we know of at least one child that was diagnosed with profound ADHD when his actual problem was nearsightedness; he wandered around the classroom not because he couldn't focus, but because he was trying to get a better view of the activities.)
Further complicating the problem is the fact that many special-needs diagnoses are interrelated, or very similar in symptoms. For example, ADHD is strongly correlated with dyslexia, dyscalculia, and several similar diseases -- but it's not associated with the autism spectrum even though it shares far more symptoms in common with mild autism than it does with any of the dys- conditions. A child that doesn't like to talk might be autistic, or they might have apraxia, or social anxiety disorder, or they might have a bad stutter... or they might be deaf and unable to hear you when you try to provoke a conversation. The point here is that special educators, no matter how skilled, cannot help a child if they're using tools and techniques designed for the wrong disorder.
Special Needs is Not 'Remedial.'
The next thing to remember is that there is a large difference between 'special needs' and 'poor scholastic performance.' Remedial education and special needs education have some overlap, but they are two different subjects -- because 'special needs' can include scholastic affective disorders like dyslexia, but can just as easily include educating a brilliant but deaf student or a student with Asperger's Syndrome that is an amazing mathematician and geographical wizard, but has trouble understanding the basics of social play and turn-taking. A good special needs program understands how to deal with gifted children -- because being gifted is a special need -- as well as those that need remedial assistance. Recognizing strengths has to be part and parcel of every special child's education.
In fact, there is a special designation in special education -- '2E' -- for those kids that are 'twice exceptional,' and require accommodation in both directions. A girl that is reading three grades above the rest of her classroom, but is also profoundly affected by ADHD and requires constant attention to stay on task -- that's 2E. A boy that is dyscalculic and cannot perform mental arithmetic, but is also a musical prodigy that masters new songs within days -- that's 2E. And these children are more common that most people understand.
The Same is True at Home
If it's not obvious, these two overarching principles apply just as much to all of the lessons you teach your child at home as well. If you refuse to acknowledge that your child is different than the others, or if you assume that the problem is one thing without getting an expert diagnosis, you're making a dire mistake. Similarly, learning that your child has dyslexia or ADHD doesn't mean you have to treat them like they're not as smart as a 'normal' kid -- they are, they just have an issue they need your help overcoming.
Special Education Tools
Here are the biggest, broadest tools of special education, and how they relate to those principles:
The Individualized Education Plan (IEP)
The keystone of modern special education, IEPs serve as record-keeping, as a source of information for future educators, and as a tool for assessing the child's progress. Each IEP contains information about the child's diagnosis, known expressions thereof, and a record of every technique and tool used in the attempt to educate the child. Without an IEP, there is no individualization -- and thus, there is no special education.
Your child's doctor and/or the school's specialists will tell you if they've been diagnosed with a condition that puts them in the 'needs an IEP' category. Not all children with a given diagnosis do -- there are plenty of kids with ADHD who get by in mainstream school with no IEP, for example -- but there are absolutely those who require special effort even if they receive and properly use a prescription such as Concerta or Adderall. Deciding whether a given child can cope with the school system 'as-is' or whether they require legitimate specialized education is part and parcel of the process.