The first decision on any graph is which quantity goes on which axis, and physics uses a clear convention. The manipulated variable, the one you deliberately change, goes on the horizontal x-axis. The responding variable, the one you measure as a result, goes on the vertical y-axis.
In a Hooke's law experiment, for example, you choose the load and measure the extension, so load is plotted on the x-axis and extension on the y-axis. Following this convention makes the gradient meaningful and matches how the relationship is usually written.
Each axis must be labelled with the quantity and its unit, written as quantity divided by unit, such as Load / N. A graph without labelled axes cannot earn full marks no matter how neat the plotting.
Deciding the axes correctly at the start prevents a graph that is technically well drawn but analysed the wrong way round.
What examiners award
Marks are awarded for putting the manipulated variable on the x-axis and the responding variable on the y-axis, and for labelling each axis with the correct quantity and unit.
Common mark losses
In short
By convention the manipulated variable goes on the horizontal x-axis and the responding variable on the vertical y-axis. Getting this right sets up the whole graph.
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)