Improving sight-reading technique

Has anyone had to take sight-reading tests for graded piano exams?

I did - I can’t say they were my favourite part of the exam, and I think I was a fairly average sight-reading student.

Perhaps Fergus Black’s Teaching Piano Sight-Reading would have helped.

Firstly, it distinguishes practicing for performance from sight-reading.

It then works through common problems, such as difficulty identifying note pitches or chords, difficulty playing both hands at once, looking down at the keyboard, disjointed phrasing, and rhythmic problems, and offers practical solutions and resources.

A useful guide.