Follow this checklist for finding out whether a mole is more likely to be normal or a melanoma:
Asymmetrical - the mole is not symmetrical, one half is different in shape from the other.
Border - the border is ragged or notched. Most normal moles have regular borders
Colors - while most normal moles have just one color, melanomas often have two or more.
Diameter - the diameter of a melanoma is greater than most moles (1/4 inch or 6mm)
Elevation - when touched the melanoma will feel slightly raised above the skin