Here is one way to remove the tics entirely from the plot. This gives a clean and simple appearance for applications where you need an illustration and the reader is not expected to glean quantitative information from the graph.
A ticless graph is accomplished very simply. The following script produces the figure following it:
unset tics plot [0:2*pi] x**2*sin(x)
The highlighted line simply tells gnuplot to not draw tics; we still get a border around the plot, but no tic marks, and consequently, no numerical labels on the axes.