Illustrator has some wonderful graphic tools, so make use of them. The star tool can add a kitsch effect. Click on the Rectangle tool and scroll along to the star, then click on the artboard and enter the values required. Colour gradients always add a satisfying depth, and you can also break your faded gradient into tonal bands (select the object with the gradient, then click Object>Expand and decide how many bands of tone you require).
Look at your masterpiece as a whole, and to ensure the character fits comfortably into the scene, consider adding a shadow. Use the pen tool to draw the shape then select a darker tone of the colour you have on the ground, and reduce the opacity (Window>Transparency) to suit.
If you are keeping the outlines on your illustration, make sure they are all correct and of a balanced thicknesses throughout. Thick lines in the distance can make a scene look incredibly clumsy. If you have text, whether it’s a title, tagline, or in a speech bubble, take some time to choose a font that suits your character’s personality and the style of the scene. If you continue to use your character, the font may be a useful branding tool for future creations.