As mentioned at the start of this tutorial, the Gradient Mesh tool lets you selectively apply color using a mesh. One note about gradient meshes: if you change your mind and don't want to use a mesh after all, the only way to do that if you can't use the undo command is by deleting the object. Once it's a mesh object, it's always a mesh object...so make sure to save a copy first if you might change your mind!
One other very important thing you need to know about the Gradient Mesh tool is that it only works on objects with a solid color fill. If the object has a stroke, using the Gradient Mesh tool will remove the stroke. (Note: If you have an object with a gradient fill, you can't use the gradient mesh tool on the object unless you convert it to a gradient mesh object. You can convert to a gradient mesh object by going to Object > Expand.)
Step 1. Control + N (File > New) to start a new document in RGB color mode. Follow steps 1 through 7 to make the first leaf of the shamrock. Shift + X to fill the shamrock with green and remove the stroke.
Step 2. In the Swatches palette (if you do not see the swatches palette, open it from Window > Swatches) open the options menu and choose Open Swatch Library then select Forest from the list. (In Illustrator 9 or 10, go to Window > Swatch Library. This particular set of swatches comes with Illustrator CS, but you can find greens in other swatches included with Illustrator 9 or 10.) You'll have some nice green shades to choose from. Set the foreground color to one of the darker greens (several shades darker than the base color of the shamrock leaf) by clicking on the chip.
Step 3. The Gradient Mesh tool looks like this: You can find it in the toolbox next to the gradient tool. Click on the tool to activate it. By clicking on the shamrock leaf you add a mesh point. The points are connected by mesh lines. Each time you click, another mesh point and mesh line will be added. Color---even a different color---can be added to each of the points after the mesh is made, or you can add color as you make the mesh. Click with the gradient mesh tool a bit above and below the center points of the heart shape as shown below to add two mesh points. Notice how the mesh points are joined by mesh lines, and there are bezier handles that can be used to alter the lines of the mesh.
Step 4. Click away from the shamrock leaf to deselect. (Click away means click an empty spot on the artboard). Change the fill color to a lighter color of green. After changing the color, you can select the shamrock again using the Selection tool (V), and click with the gradient mesh tool again to add some lighter spots on the shamrock on the right and left side of the leaf as shown below.
Things to remember:
Step 5 . Notice you now have even more bezier handles you can use to adjust the mesh curves as well as the ability to move the points by dragging them to place the color where you want it. If you need to, you can use the Direct Select tool (the white arrow, keyboard shortcut A) to click and drag to move the bezier handles to make the mesh fit the shape of the shamrock. Zoom in if you need to get closer to see well enough to grab a handle.
Step 6. Change to the selection tool (V). Make sure the leaf is selected. Activate the Rotate tool in the toolbox, and Alt + click on the leaf in the same place as you did on step 8 of the "Drawing the Shamrock" section above.
Step 7. In the Rotate options enter 100 for the angle, and click the Copy button. This will rotate the leaf and make a copy at the same time. Clicking the preview checkbox allows you to see where the new leaf will be placed.
Step 8. The Rotate tool should still be active in the toolbox. Select the first leaf again, set the point of origin as before, and using the Alt key, click the cursor just above the bottom point of the leaf. This time set the Angle of rotation to -100°, and once again, click the Copy button. You should now have three shamrock leaves.
Step 9. Use the selection tool or the arrow keys to move the leaves into a shamrock formation. Click the first leaf (the top one) with the selection tool to select it and move it to the front (Object > Arrange > Bring To Front).
Step 10. Now we need a stem. Activate the arc tool. It's on the Line tool popout menu. (If you have Illustrator 9, you'll have to draw the stem with the pen tool. Make a curved line). Draw an arc about a inch or so long. In the stroke palette, set the stroke width to 10 and choose rounded ends for the stroke. (If you can't see the stroke palette, go to Window > Stroke to show it.)
Step 11. We need to make the stem into an object; right now it is a stroke, the same as when we drew the first shamrock. Go to Object > Path > Outline Stroke. Before you could see the stroke; now you can see points around the shape.
Step 12. Use the gradient mesh tool to add some shading to the stem.
Step 13. Move the stem to the shamrock, and rotate if necessary as before. Send the stem behind the shamrock. (Object > Arrange > Send to Back) Select all four pieces and group them (Object > Group or Control + G).
Step 14. Add some text, fill with a gradient, and warp it. To do this you will have to follow several steps. Text can't be filled with a gradient unless it is turned into outlines.
1. Type the text.
2. Click the Selection tool so you have a bounding box around the text and go to Type > Create Outlines. Now you can fill the text with a gradient the same as any object.
3. To warp the text go to Effect > Warp > Arc. This text is set at Horizontal at 50%. The rest of the settings are left at default.
And here is the final image! Happy St. Patrick's Day!