A basic knowledge on how to use the pen tool and how to draw bezier curves is needed to get started with this tutorial.
Draw a curved line that looks similar to the illustration above. Hold down the shift key while dragging the handles in the last point of the curved line. Drag a vertical guide onto the curved line as shown in the picture above. To make it snap to the exact position, make sure that Smart Guides is checked (View > Smart Guides or command/control + U). Step 2 - break the curve into 2 parts
Because we‘ll have to apply different shades and we need to create depth into the ribbon, we need to cut the ribbon into different segments.
Select the Scissors Tool and click on the location on the path as shown in the picture above. With the Smart Guides active you‘ll get the ‘intersect‘ text when your cursor is at the right spot. Now the path is cut into 2 segments. Select both segments, hold down the shift + option/alt key and drag/copy the paths vertically as shown in the picture above. Step 3 - close the paths
Close the paths as shown in the picture below, so the ribbon exists of 2 segments. Select both segments, select the Rotate Tool and click while holding down the alt/option on the location as shown below in the picture, enter 180° and click the Copy button.
Advanced users will probably just click on the exact location, hold down the alt/option and shift key while dragging the segment to the correct location as show in the picture below.
Chances are that both segments don‘t perfectly match. Select the 2 new segments, zoom in, and drag them to the exact location. With Smart Guides still checked it‘ll snap and you‘ll see the word ‘origin‘ appearing. Step 5 - merge the middle segments of the ribbon into 1 segment
Select the 2 middle segments of the ribbon and click on the "Add to shape" option in the Pathfinder palette. This way Illustrator will treat these parts of the ribbon as 1 object which will make it easier when we give this segment a fill.
Our ribbon is now divided into 3 segments. All we need to do now is give each segment its own fill. To add dimension and depth we need to use a different (linear) gradient on each segment:
First segment gradient consists of : 50% cyan and 7% magenta, 32% cyan and 4% magenta, then again 50% cyan and 7% magenta followed by 69% cyan and 10% magenta.
Second segment gradient consists of the following swatches : 67% cyan and 15% magenta, 50% cyan and 7% magenta, then 23% cyan followed by 31% cyan and 5% magenta.
Last segment gradient consists of : 50% cyan and 7% magenta, then again 50% cyan and 7% magenta followed by 31% cyan and 5% magenta.
You probably have to use ‘Send to back‘ or ‘Bring to front‘ on the different segments to get them into the correct perspective. Step 7 - fine tuning the centered curve of the ribbon
As you probably have notice, the curve in the center doesn‘t look that natural. That‘s because I drew that part holding down the shift key, but this was needed to make sure the rotated ribbon would match perfectly on the original one. I can correct this very easily, but first I need to expand the 2 merged segments. Select both segments and click ‘Expand‘ in the Pathfinder palette. This way the vertical line connecting the 2 segments disappear and we have only 2 bezier points left. Now it‘s a matter of dragging the handles into the preferred position to smooth the curve of the ribbon.
Ah! Much better don‘t you think? :)
You can make the ribbon larger by copying the entire ribbon and paste it next to the ribbon. You can also merge the middle segment that connects the 2 ribbons. Then you can select the entire ribbon and use the Free Distort Filter to achieve extra depth. Last but not least you can rotate the ribbon. That‘s what I did in my illustration.