Use Preset Shapes to create the shamrock. If you have a shamrock shape, that's great! If you don't, you can create the shamrock from 3 hearts. If you don't have a heart preset shape, you can download one here.
Draw a green heart shape in a size appropriate for the stem. Duplicate this heart using right click - Copy - Paste as New Vector Selection (twice).
Use the Pick tool and the rotation handle to rotate all hearts and move into position as shown in the above image. Use the Pen tool and draw a light green highlight line on one side of each 'petal'.
If you feel there's too much black outline in the center of a shamrock built with 3 hearts, you can cover center of each heart with a plain green circle or do a little editing to get rid of some of the outline. Right click, 'Convert to Path'. Select the node that is at the point of the heart, right click, select Edit, Break. That will break the one node into 2. Now you can move these nodes to 'shorten' up each heart and to connect lines to look more like a shamrock leaf.
