Graph plotting is an art, which is why I don't let my students use computers to do it. Once they've served their apprenticeship, fine, but not until then. The essentials in my scheme are

• the graph should be pleasantly proportioned; this means axes of equal length or in a ratio of roughly 2:3, either landscape (page sideways on) or portrait (page normal);
• the axes should be ruled and have sensible divisions; this means each square is 1, 2, 5 or 10 units (or multiples or sub-multiples). Don't use 3 or 7 units per square! You will mis-plot the points. Graphs take a long time for relatively small return, so make the plotting as easy, therefore as fast as is possible.
• the points must remain visible once the line is drawn; use crosses, or dots with circles, or if you know the error magnitudes, error bars;

BE CLEAR about the nature of your graph - does it represent a continuous relationship needing a smooth curve, or a discontinuous one (e.g. something like ionisation energy plotted against atomic number), where the lines joining the points should be straight? Make sure you know before you join up the points.