Ditch the pick up lines and use lines that apply to the situation at hand. If you're in a video store it seems left field if you ask her if she like to brush or floss first. You could ask her what movie does she prefer or you can give her your opinion on what you think she may like. This approach actually can lead up to a movie date. You also appear to be more confident because you're approaching her without the need for a corny pick up line. This isn't restricted to video stores.
There is no limit because the situation always changes. It also prevents you from coming off as cheesy because what you will be saying will be relevant and it makes her respond to you, keeping the conversation going.
If you thought this was helpful there's more where that came from.