My way of doing it would phase out the other taxes, and require the receipt to enumerate the sales tax as a specific line item.
That would leave ONE tax line item, and Joe Citizen suddenly notices that he's paying 35% on every transaction. Gasoline would cost a s**tload less, IF the sales tax went down. Food would cost a s**tload less, IF the sales tax went down.
Eliminating withholding by itself would swing a lot of folks to the smaller government; I don't think you'd need a flat tax per se to do that.
I'd also move tax day to the day prior to election day.
I'd prefer to move election day to April 16th or the first Tuesday after Tax Day. That way, taxes wouldn't interfere with saving for Christmas and Hanu--er, holiday shopping, and the weather for election day would probably be better, resulting in a larger turnout.