Try outline weights of 1 or 2 rather than accepting the default 0.1. Try one basic color scheme first. It may be best to stay with one basic color scheme if only three classes are used. Two blues and one green may not be pleasing to the eye, especially if there is equal intensity on two of them. Three different colors may be ok, but they should have high, medium, and low intensities.
Patterns can be useful, either for monochrome maps or to add difference on colors.
Density of patterns can help establish class differences. They may be very useful when using five or more classes. However, be careful. The plotter gives darker colors than are seen on the monitor, so a medium blue may be plotted dark. You may have to lighten each class 1-2 levels before plotting.