This is what I do...stop at the paint store and pick up paint cards...then I take them to the fabric store.
One tool that has helped me is the 3-in1 Color Tool by Joen Wolfrom
http://www.ctpub.com/productdetails.cfm?PC=808
I take this with me always to the fabric store. Using this tool, I have become more aware of the 'undertones' of a color.
I think tropical colors will be beautiful. Browns can have more of gold/orange tones which would be beautiful with the greens and the coral.
Have fun with your project!!
FW