You should give the car a polish after the second wash (post claying) and then apply your last stage protection (sealant/wax) after this.
I use Dodo Juice Purple Haze wax on my car, but I have a black car. Dodo Juice Light Fantastic would be more suitable for your car as its designed for light coloured cars, I haven't tried it myself but the Dodo Juice range seems to be highly thought of.