Bold Colours were all over the spring 2011 runway last September + no one did it better than Jill Sander. Her mix of brights + stripes is very inspiring.
I think that the key to wearing bold colours is finding a colour that looks good on you + sticking to that color/hue. Also, don’t be afraid to mix bold colours with each other.
Lastly, if a bright bold shirt isn’t for you, or you just can’t see yourself in bright green pants, choose a bright accessory instead.