Graph questions reward care, and most lost marks come from a small set of repeated mistakes rather than a lack of understanding. The most common are axes without a quantity or unit, and scales that are awkward or too cramped, which make the whole graph harder to plot and read.
Next come imprecise points marked as thick blobs, and best-fit lines that are drawn dot-to-dot, forced through the origin, or pulled off course by a single outlier. Each of these quietly costs marks that were within reach.
When finding the gradient, using too small a triangle or forgetting the unit are frequent slips. And reading an intercept off an axis that does not start at zero gives a wrong value.
The fix is a short checklist run before you finish: are the axes labelled with units, is the scale sensible, are the points precise, is the line balanced, and does the gradient carry a unit. A minute of checking protects several marks.
What examiners award
Marks are awarded for labelled axes with units, a sensible scale, precise points, a balanced best-fit line, and a gradient quoted with its unit.
Common mark losses
In short
Most graph marks are lost to a short list of avoidable slips: unlabelled axes, awkward scales, imprecise points, poor best-fit lines, and gradients without units. A quick checklist catches them.
A routine that works
Practise the mechanics until they are automatic: label both axes with units, choose a scale that fills more than half the grid, plot points with a sharp pencil, draw a single best-fit line, and take the gradient from a large triangle with its coordinates and unit shown. One clean example beats re-reading the theory.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)