I will give you a run down of the most stereotypical visual traits for both witches and wizards in modern perceptions of folklore and fairytale, you should be able to use these.
Wizards almost always wear flowing robes, often presented blue in colour, but they can be any colour, while witches are often portrayed as wearing solemn black dresses and pointy boots. Wizards and witches both often wear conical, wide-brimmed hats, that sometimes point straight up but can also be floppy. Sometimes wizards have some kind of a pattern on their clothing, often of a cosmic theme (planets and stars.) Wizards sometimes wear spectacles.
Wizards usually carry a staff or wand, witches can carry either as well, but may just carry a flying broomstick instead. Both witches and wizards can have familiars, which are animal companions such as an owl or toad, for witches it is almost always a black cat, which symbolizes bad luck. Witches and wizards can make magic potions, and witches are often seen being near a large cauldron where they brew them. Wizards may carry around or have a large library of spellbooks and magic scrolls. Either might also have a crystal ball to look into the future, into the past, or spy on people and just see far away events.
Both are seen as old, perhaps to reflect a wizened and knowledgeable image for them, but for witches it may be for more of a scary "hag" image, and witches can be very ugly as well, complete with pointy noses and chins, and facial warts. Sometimes witches are given green skin as well, for some reason. Old wizards almost always have grey or white beards, that can be very long, perhaps to again reflect the idea of age and wisdom.
Hopefully that helps.