Suede is a form of leather made from calf skin, and is notoriously hard to clean. Because of the textured feel of suede, it is difficult to remove stains as you would from normal leather. If you do end up staining a piece of suede, don't think it's completely ruined. There are things you can try at home to get the stain out and revive the material.
The first thing you should after investing in a suede item is to buy a suede brush. This inexpensive tool pulls up the fabric texture, making it easier to clean. Always use the brush as your first step in cleaning. The brush helps break up some of the stain.
Before you do anything else with the suede material, read the care instructions. This will give you a good indication of what not to use to clean the suede. Some suede is synthetic and easier to clean; the instructions will be able to tell you if this is the case.
You want to keep from getting suede wet--one of the reasons that makes it so hard to clean--but you can use the power of steam to help you. Hold a steam iron about 6 inches over the surface of the material. Make sure to hold the iron close enough that the stain is steamed but far enough away that any water from the iron does not drip on the fabric. Once the stain has been steamed, try to scrape it away with fine sandpaper or a razor blade.
When cleaning suede, be careful not to use any water. When you are trying to wipe away stains and marks, use a soft, microfiber towel so as not to damage it. If you are having trouble with some stains, try a pencil eraser for a dry solution.
If you absolutely need to use a wet solution, try pouring some white vinegar on an absorbent cloth and rub the stain until it is gone. If your shoes get water-stained, let them completely dry before attempting to clean. Once they have dried, use the suede brush to remove the water marks. If the marks are very bad, a last-chance method is to soak the entire piece of suede in water to see if it will all blend together when dry. This technique, however, is not always recommended and should only be used if the piece is otherwise ruined.