That seems to get the basic shading, but you have used a repeating transparency instead of a linear gradient fill. I find that approach can get complicated. Best to use a solid base shape for each colour and start with a fill, then lay transparencies over that, only where a transparency is needed. Now draw the shadow area and make another linear gradient fill with a darker shade. Don't forget to use the colour palette; Ctrl+E, for the easy adjustment of shades on your gradient.

After that a few subtle highlights; -white with transparency and feathered edges, should do the trick.