Meet with the director and design team. Opera is a collaborative art and many people will have opinions about the costume design. Important voices will include the stage manager, scenic artists, cutters, sewers, buyers, wig makers, and, of course, the opera singers.
Study the opera. Familiarize yourself with the scenes. Which scenes will require special dramatic impact? One of Hall's most dramatic costumes was a ruby red dress for a wedding scene in Vincenzo Bellini's opera, "I Puritani," a drama about the Puritan era.
Take measurements. Make sure the subjects are standing upright when you measure. In addition to body measurements, such as height and chest size, also measure head circumference for wigs and feet for shoe size. Avoid designs that will constrict the singers' necks and chests. Allow for movements, such as kneeling or striding. Keep in mind that many opera singers prefer not to have their heads covered.
Sketch out rough designs, focusing on shapes and color schemes. Different time periods are characterized by different shapes. For example, Tudor costumes have square shapes and Victorian ones have bell shapes. See the way the shapes fit together.
Choose a color palette. Opera costumes tend to have bright hues, but sometimes dark colors are called for. In Giuseppe Verdi's opera, "Don Carlo," King Philip must wear black. To avoid having the costume look dead, the designer needs to play different black fabrics against each other, such as silk and velvet. Gold stitching can bring out shading.
Buy swatches of material. Because opera tends to be performed on large stages, bold, strong fabrics are needed. Designers often use upholstery fabrics, such as velvets and brocades.
Emphasize shape or color with trimmings. Lace, buttons, braids and pearls can add character.