We need to know more about the variables and features being symbolized. Can you post an image of the legend to these symbols? Or describe what the features are and what's being symbolized by the color and size changes?
In general how you symbolize is dependent on the type of data, if its qualitative or quantitative. Use different symbol shapes or color hues for qualitative variables (feature types), use size and/or color value (shading) to symbolize changes in quantity or order.
Both the circles and triangles on your map vary by size and color value but the relationship appears to be linear, i.e. the color changes in step with the symbol size (small symbols are darker, larger symbols are lighter). Are you symbolizing two independent variables for each feature or using both size and color to symbolize the same variable?
Here are some more general notes on the map design:
1) The suggestion to move the graticule to the background is a good one. I would also suggest you use a lighter gray or even a light blue.
2) the lower map shows a coastline casing, the upper map does not, standardize this.
3) the green coastline adds to the map complexity and is distracting, use a more natural color like a slightly darker blue than the water (or get rid of the casing all together and use a darker grey fill for the land masses)
4) you can get a better scale on your upper map by rotating it so the Aleutian chain stretches more horizontally across the page and move the inset to the upper right where it is out of the way.
5) your N arrow isn't pointing to true N. Really this coordinate system doesn't allow for a N arrow anyway since the angle to N changes as you move from East to West along the page. you also don't really need a N arrow if you use a graticule (and a locator with inset frames).
GIS Reference and Instruction Specialist, Stanford Geospatial Center.