• Just tell the potential customer that you just can't do it now. But don't ever, ever, stop there. Give a referral. You may find that they would be willing to wait a bit for you. And this is no time to tell them how great you are, how lucky they would be to have you on the job, how many other customers you have waiting in line for, that sort of thing. And don't tell them to look up something in Google. Give them the name, the telephone number and the website of the person or company that you are referring them to. Keep that information handy so that it only takes you a few seconds to find it.
• Have an emergency rate. In my industry, they are called *rush jobs*. But don't make big deal out of it, just say, yes, I can have that for you, this is the price. But be very, very careful with this one. This is assuming that you can expand your regular workday. When I had clients ask me to do this, when I was freelancing Graphic Design, I would stay up all night. An emergency rate should be slightly higher than your ordinary rate, not so much that it looks like you are ripping someone off, but enough to make the extra effort worth it.
• Accept the job and hire someone else to do it for you. I really don't recommend this, unless you know someone who is as good as you. If you hire someone who needs a lot of hand-holding, you are better off doing it yourself. And remember that it's your name on the job, you have to responsible for the quality. I tried this early on in my career and found that my nervous system couldn't take it.
Sometimes saying *no* can be the most positive thing that you can say. But be nice!