I have difficulty reading charts. My eyes don't focus in the same place, so following a line across can make an otherwise pleasant fiber experience harrowing.
I often make patterns using magazines or books, which will not fit on a standard chart-reading thingy.
I found a great solution.
Some businesses give away promotional magnets for the fridge. I took the largest of these, sliced that puppy across its length and voila, a handy dandy chart line marker.
I took one part (the larger, if they are different sizes) and put it face down (magnet side up) on the page beneath the chart. I took the other piece (face up) and carefully lined up the straight edge above the row I wanted to work. All rows above are blocked from sight, I need only concentrate on the row below the magnet edge, and when I finish a row, I just move the magnet up one.
It worked great, as my ogee skirt can attest. It was the first time I successfully made anything using a chart.