Symbols need to be 2 to 3 times the width of the curve to be distinguishable after the figure is reduced. If symbols are not used, different line patterns may be needed if the curves cross one another. Bars should not be three-dimensional. The axis and axis label of a bar graph should follow the recommendations for a line graph. The bars themselves should also be labeled.
Bars are one-dimensional and individual bars within each group are distinguished by shading.
The legend is placed within the body of the figure. When submitting a figure to the Journal, keep in mind that unless the figure is unusually complex, it will be reduced to fit in one column on the page. When reduced, all letters on the figure should still be legible. Check how your figure looks when reduced before submitting it. All figures in an article that are related to each other should be submitted in the same format and be the same size.