(swamp by Lawrence Whittemore, licensed under Creative Commons.)
Hold that feeling in your mind and the expression on your face is going to resemble that of someone picking up a cocktail list for the first time. It's something I see quite a lot at work, that mix of curiosity and utter, utter fear. Some of those exhibiting the look of rabbit soon to lose its third dimension ask for help, some don't.
True story: two girls come up to the bar and ask for two martinis. I get the sense that they're not big martini drinkers, so I try offering them something a little easier-going, a softer twist on the classic recipe and they're all, "no, we want martinis." Five minutes later, they come back: "can we get some lemonade in these?"
My usual gambit at work is to ask the would-be adventurer what spirits they like and suggest flavours that work well with their favourites. At this point, I tend towards a couple of different basic drinks that lend themselves well to customization - a Sour or a Collins can work really well without much effort.
There's a fine line to be walked in mixing drinks for cocktail newbies. You might want to express the breadth of flavour available through mixing different liquors, but it's usually better keeping things simple. For the most part, I'll tend to stay away from ingredients with more complicated flavours because, being honest, it's rare that someone instantly gains an appreciation for the herby intensity of absinthe or the smoky peat of an Islay malt. Berries, vanilla, fresh fruit, these are your friends. All things considered, the drinks I come up with in this kind of situation aren't among the most developed in my notebook. Sometimes you hit it out of the park, but more often than not you get a base hit. However, the key point is it's not about how I feel about the drink.
When it comes to that guy stood on the edge of the swamp, swallowing hard and wondering what it is he's doing there, it's worth remembering everyone stood there once. Get as much information from him as you can, make a good drink and hope. Show that person that the swamp's not a bad place to be, because, ultimately, you're not the one who decides whether or not to go deeper.