How to Make a Color Palette in Illustrator

use rectangle tool to draw a square > hold alt + click and drag to copy the square > ctrl + d to make duplicates

 

use eyedropper tool to sample a color > color guide > click on square > Click a color from color guide to fill square

 

drag colors into swatch

 

* the swatch can be imported into another illustrator file by clicking the swatch library menu icon and selecting ‘other library’ and opening the illustrator file which contains the swatch