Three levels of reading

Literal, inferential, evaluative.

What each asks

Literal reading recovers what the text says. Inferential reading works out what it implies. Evaluative reading judges whether it holds up. Most exam questions target the first two.

Confusing inference with opinion is the most common error.
An inference must be supportable from the text alone.

Reading with a purpose

Knowing whether you need the gist, a specific fact or a full understanding changes how you read. Reading everything at the same depth wastes most of the effort.