Take a look at this excellent list of evolution misconceptions. The entries are very brief, but mostly correct and very common: in particular, #12, “Natural selection involves organisms ‘trying’ to adapt” is one of the most common mistakes in creationist thinking — they completely miss one of the most important insights that Darwin had.
But I have to nitpick a little bit. #6, “The theory is flawed,” gives the wrong answer — it basically tries to argue that the theory of evolution is not flawed. Of course it is! If it were perfect and complete we’d be done with it, and it wouldn’t be a particularly active field of research. The “flaws” that creationists typically bring up aren’t flaws in the theory at all, but flaws in the creationists’ understanding of the science, but let’s be careful to avoid giving the impression of perfection.
#15 is also a pet peeve: “Evolution is a theory about the origin of life” is presented as false. It is not. I know many people like to recite the mantra that “abiogenesis is not evolution,” but it’s a cop-out. Evolution is about a plurality of natural mechanisms that generate diversity. It includes molecular biases towards certain solutions and chance events that set up potential change as well as selection that refines existing variation. Abiogenesis research proposes similar principles that led to early chemical evolution. Tossing that work into a special-case ghetto that exempts you from explaining it is cheating, and ignores the fact that life is chemistry. That creationists don’t understand that either is not a reason for us to avoid it.
#13, “Evolution means that life changed ‘by chance’,” also ducks the issue more than it should. As it says, natural selection is not random — but there’s more to evolution than natural selection. It’s a bit like ducking the question by redefining the terms. Much of our makeup is entirely by accident, and evolution is a story of filtered accidents. Creationists don’t like that — one of their central assumptions is that everything is purposeful — but don’t pander to their beliefs. Go for the gusto and ask them what their god was thinking when he loaded up your genome with the molecular equivalent of styrofoam packing peanuts, or when he ‘accidentally’ scrambled the sequence of our enzyme for synthesizing vitamin C.