Blackberry you could do with working out whether this is a ‘warm’ or ‘cool’ grey. If it has a look of brownish/yellowish or pinkish tones in the grey, then they are warm; conversely, bluish or greenish is cool. Then, work on opposing colours. So, warm shorts with a cool top, say blue, dark grey, any shade of green etc; cool shorts with warmer top, like yellow, tan, red, pink etc. Flip flops? Hmm, well, tone with the shirt or top. Red for warm, green or blue for cool. I think that covers it. Of course, your own skin tones and hair colour also have to be taken into account… Hawaiian multi-coloureds go with pretty much anything, by the way :)