Pick pretty much any colour you like of plain shorts, knee length then fold them up an inch or two.
http://oi57.tinypic.com/ortgme.jpg
http://oi58.tinypic.com/bzxpc.jpg
https://s-media-cache-ec0.pinimg.com/236x/90/67/e0/9067e05520106f252d29fd4bfda4d656.jpg
I wouldn't wear pink shorts, but its not really the colour I'm showing off

Dat knee fold is the most important touch... Colours I like are navy, khaki, black, etc
As for t-shirt ideas... colourful polo shirts by Ralph Lauren (here you can go really fruity i.e. red, purple, light blue, pink etc... summer colours)
or just plain v-neck tight fitting non-branded t-shirts, show off em guns