Here are the things I look for (can you find them in my Boyle’s Law graph below?).
1. A title that describes the experiment.
2. Axes that are
(a) Highlighted (drawn darker than the rest of the lines)
(b) Scaled (in units of 1, 2, or 5 or multiples of 10 of these numbers) to fill the whole graph area
(c) Labelled with the variable name and units. Dependent variable on vertical axis; independent variable on horizontal axis.
3. A graph area containing
(a) Horizontal and vertical grid lines from the major axis divisions
(b) Plotted points marked by a special symbol (often a circle)
(c) A line of best fit that goes as close as possible to all the points without necessarily going through any of them
