The proposal that gets signed fast

You had a great call. You said you'd send something over "in a couple of days." Three days becomes a week, the week becomes "I really should get to that," and by the time you send it the prospect has either hired someone else or cooled off enough that your careful, polished document gets a slower reply than the rough one you could have sent the same afternoon. The proposal wasn't the problem. The gap between the call and the send was.