There is a vast field of research into dyslexia and other specific learning differences along with many suggestions for effective teaching strategies, such as the font style, the background colour (avoid white due to the assoc condition of visual stress), avoiding presenting text in long paragraphs and leaving a gap between lines.
Regarding undiagnosed or mild dyslexics, teaching that is good for dyslexic students should be good for all students.
I agree with Peter Samuels , but note that adults with dyslexia have often developed compensations for their challenges that sometimes make it difficult to apply the standard teaching methods used with children recently diagnosed. A thorough assessment of each person's reading strategies is therefore required in order to develop an effective tutoring technique for each adult learner.