I recommend using Meguiers Leather conditioner. Simply spray on after each wearing and wipe off. Then buff. This process will keep the shoes conditioned, clean, and shiny after each wearing. I've been using this product for many years on my FJ Classics and FJ Icons and it works great.
Since your shoes are white, if they get scuffed or black marks, use a TINY amount of SoftScrub on your finger and GENTLY rub it into the leather. There are abrasives and bleach in the stuff, so be extra careful. Once done use the Meguiers and you should have nice and clean shoes time after time.