Cartesian graph paper with numbered axes, A4
Axes through the center, numbered in both directions, on A4, the sheet for plotting functions that go negative, which ordinary graph paper handles badly.
Opens with these settings already loaded. Change anything you like, then download as PDF, PNG or SVG.
Four quadrants, not one
Plain graph paper implicitly assumes everything is positive: you put the origin in a corner and work up and right. That falls apart the moment a function crosses an axis, and students end up redrawing the whole plot. A centered origin gives you all four quadrants from the start, which is what almost every school and undergraduate exercise actually needs.
Numbered ticks prevent the most common plotting error
Counting squares from the origin every time is where errors creep in, particularly on a fine grid where it is easy to be one square out and not notice until the curve looks wrong. Printed numbers on both axes remove that step. They also make the finished plot readable by someone who was not there when you drew it, which matters for coursework being marked.
Choosing a scale before you start
The single most useful habit is deciding your scale before the first point goes down, based on the range of the data rather than the size of the paper. A grid at 5 mm on A4 gives roughly 38 squares across and 55 down inside the margins; pick a scale that puts your full range comfortably inside that, in round numbers per square. One unit per square is easiest to read, two or five are acceptable, and three or seven will make the plot hard to check.
Printing it accurately
This only measures correctly if your printer doesn't rescale the page. In the print dialog set Scale: 100%, not "Fit to page" or "Shrink oversized pages". If you're not sure it worked, print the calibration page, measure the ruler on it with a real ruler, and it will tell you exactly what your printer is doing to the page.