In hot weather, sometimes an iced coffee can be just the thing. Here's my recipe (makes about a pint / 550ml).
Needless to say, as with all things coffee, GIGO. Garbage in, garbage out. That's to say: Start with good quality coffee beans. I'd recommend something medium-light roasted. If you roasted yourself, dump no later than the very beginnings of second crack. If you've bought the beans roasted, go for freshly roasted ones without oils showing.