When a child is struggling in school, we have three choices for ways to help. We can remediate, accommodate, or teach the child to compensate.
If at all possible, we should fix the problem. The best example of this is a child who does not read well. Maybe she has trouble figuring out the words on the page, or she can read the words but cannot understand what they mean. If we set up a program that teaches them how to read better, we are remediating or fixing the skill deficit. This is ideal. When possible, problems children have in school should be remediated. This can take a long time depending on the severity and type of problem. Sometimes it requires a specialist trained in remediation.
Other things that help can take less time and effort. Often, students can learn to manage their own problem. For example, if one of my students can spell pretty well but still makes errors, I teach them how to type and to word process their work so that the spelling checker can point out which words are misspelled. This is called compensating for the skill deficit. The student handles the problem himself.
Unfortunately, some problems cannot be fixed (or will take a long time to fix), and the child cannot manage them on their own. If a child has extremely poor eyesight, we must make an accommodation for the problem. For a variety of reasons, I might give a student near-point copies of notes and diagrams I put on the board. If needed, as for the child with poor eyesight, these near-points can be enlarged on the copier. With this simple accommodation, the child can succeed in my classroom.
Many compensatory strategies and accommodations require little effort on the part of the teacher. Once a child learns a compensatory strategy, they do it for themselves. Doing something like providing a copy of my notes for the student who needs them, takes very little time. Something very simple can make the difference between failure and success for a struggling student.
For a very long list of possible accommodations check out this article.