Adobe once owned a program called Streamline which was a utility for converting bitmapped images into vectors. Though they have now discontinued it, Streamline lives on in the guise of Illustrator’s Live Trace function. This allows you to convert bitmaps imported into Illustrator into vectors, either by choosing one of the preset settings or by creating a custom set of parameters. The program is very fast, so it is easy to experiment with several different settings to see what gives the best results. Once you have got your vectorised version of the artwork, you spend a bit of time cleaning it up and it’s good to go. You can Try this out on Adobe Illustrator Site.
Scanned or other images can also be placed on a background layer and used to provide constant points of reference when originating new Illustrator artwork. Background images can help to ensure that elements within the Illustrator artwork you create are of the correct dimensions have the correct relative proportions and so forth. For example, if you are drawing human figures, placing a photo of some people on a background layer can help to ensure that you don’t end up creating figures with disproportionately large heads or long arms.
Almost all drawings you create will contain elements that either repeat or are variations on the same theme. Naturally, you will not create such elements from scratch each time you need them. Illustrator contains a wide variety of useful techniques for duplication and transformed duplication of existing elements within your drawing. It also allows you to apply multiple attributes such as fills and strokes to the same object. Thus, for example, you can create the appearance of several concentric circles simply by adding several strokes to one circle (using the Offset Path effect to get the right position). The bottom line is that Illustrator’s blank canvas doesn’t have to stay blank for very long. You just need to formulate a clear idea of what you want to achieve with the program. Wherever possible, find images which you can either trace or use as reference points as you originate your own artwork.