Hard wax: Foam pad
Soft Wax: Microfibre
I've got some dodo, tried applying it by hand and by foam app and either works well, although you'll use much less by using an app.
The idea behind applying it by hand is that everything out of the pot goes onto the panel as your skin is waterproof, rather than a foam app possibly absorbing some of the ingredients of the wax (which could be detrimental to the finish, durability etc). You'll get a more even application with the foam app though.
Try it by hand, it's pretty fun
QD - I usually finish off with some last touch as it just refines the finish a little and helps remove any holograms. As gal said you can use some cold mineral water in a spray bottle, using this method is more worthwhile on natural waxes.