Edwardian architecture is the style popular during King Edward VII of the United Kingdom's reign; he reigned from 1901 to 1910, but the architecture style is generally considered to be indicative of the years 1901 to 1914.
Colour: lighter colours were used; the use of gas and later electric lights caused designers to be less concerned about the need to disguise soot buildup on walls compared to Victorian era architecture.
Patterns: "Decorative patterns were less complex; both wallpaper and curtain designs were more plain." 
Clutter: "There was less clutter than in the Victorian era . Ornaments were perhaps grouped rather than everywhere."