I don't know if you're from the US or what, but if you are, I think your boss is silly to give you an assignment like that.
Personally, all of my favorite cocktails have involved peaches. One place had peach puree with peach schnapps and champagne, which was amazing, and I had one recently that was peach schnapps, orange juice, and vodka. But I like fruity things, so some sort of puree or juice (peach, orange, cranberry, etc) mixed with two alcohols, one of which should have a fruit flavor, would be really easy. Vodka or white rum would probably be an easy alcohol to start with.
Really, I think you should buy a book of mixed drinks and base things off of what you like (if you've had good mixed drinks before). If not, ask someone you know who knows their alcohol to help you taste test things.