Despite taking good care of a pair of shoes, they will start to look boring. When they do, it's probably time to give them a good wash. Don't believe that water can ruin the suede, it will be all fine. Suede can handle a lot more then people think.
Remove the shoe laces, brush the shoes free from sand and dust.
Wash the entire shoe with water and make sure to wet all of it.
Read the instructions on the packaging of the schampoo to make sure to apply it correctly. Different brands and types of leather schampoo has different instructions, but most common is to apply it to the shoes with a brush and then rinse thoroughly.
Let the shoes dry for at least a day with shoe trees inserted. The shoe trees make sure that the shoes will maintain their shape. Let the shoes dry on their side, like the picture shows, to make sure the soles get a chance to dry.
The shoes are dry and clean! To prevent them from becoming dirty again, treat them with waterproofing spray. Read how to do it here!.