Observe a student in the classroom. If they refuse to take part in reading activities, don't want to read, and dislike books and reading, they may have a reading problem.
Reversing words in a passage after the age of 8, skipping, guessing, misreading words, and giving up easily are characteristics of someone with reading problems.
Hiding a lack of reading skills by making excuses can be a sign of reading problems.
Sounding out words instead of trying to figure out unfamiliar words by how they're used in a sentence can be a sign of a reading problem. Watch for a student with low self esteem who uses a lot of side to side and up and down eye movement. Reading without accuracy can signify a struggling reader.
Evaluate students using educational, speech, language, and intelligence tests. Rule out the possibility of physical problems, bad attendance, family conflicts, and lack of instruction.