That's going to sound sacrilegious to some readers, who have been brainwashed into thinking that if you're not wearing the "correct" camo pattern, you're just not a serious hunter.
Clothing should not only be scent free, but also as silent as possible. Nylon should be avoided. Obviously, outer clothing also must comply with state regulations regarding “blaze/hunter orange” requirements.
Camouflage clothing is not necessary; but the cloth selected should be soft and noiseless as possible. A mix of drab colors will work fine as long as they are scent free and quiet (and warm if hunting during colder months).
A deer’s hearing is second to its sense of smell as a defense mechanism. Unnatural noises, even subtle sounds like nylon rubbing against each other, can alert them to your presence.
Proper clothing will also keep you warm and dry. Dressing in layers, and avoiding cotton will help keep you warm and dry. Modern synthetic clothing and wool are excellent choices. Some excellent clothing may be found inexpensively at used clothing or Goodwill stores.
Rain gear is a huge asset during inclement weather. Occasionally, rain gear or cold weather clothing may be lent to participants by the program or mentor/guide.