Or do it like i did;
-Wash the car properly.remove all stain there is on the body.use a bit of pressure on the bumper.wipe the car dry.
-use a polish.i have a clay bar but only my bro uses it.its effective but i only uses polish.cheap polish like soft 99 have quite strong power to remove dirt.take your time,do a panel at a time.i did it 3 panel at a time.Lower door,behind all 4 tires,bumpers and front bonnet are the part i took most of the time.only apply a thin layer.
-when the polish is removed,relaxed and have a cigarette or tea.inspect the car all around to see if u miss anything or some dirt still sticking.
-apply a layer of wax.currently i am using turtle wax platinum.very easy to use and can be applied on plastic too.for best result,buff abit.
anyway,i am just basic detailing guy.u wont belive what others did.
the easy part is the big panel.fyi i also wax and polish the inner doo panel,sill and area that i can reach on the bonet.
dont forget to clean wax or polish residue on the panel gap.
sometimes its not the brand of the wax or polish.its the quality of work.it will consume time but its worth it esp when someone said 'cantik bang,hantar kedai mana?'.