You need a process. It should never be just about "what do you think looks good?". Talk to the customer, find out what they are thinking about, generate conversation about what they like or don't like, how much maintenance is a concern, and throw out suggestions to them to see how they react. Most of all, tell them why this would be good or that would not be so good. There is no faster way to get a conceptual design done than through conversing with your client.
You don't need to ask for a direct budget, but listen to the materials they are talking about and try to pick up on the subjective budget.