Dean’s style is a mix of work and military. Mostly brown and green tones, lots of pockets and sturdy boots.
If you want to try it out, Dickies or Carhartt shirts are always a good choice. Combine it with a t-shirt in solid black, white or khaki and you get a good match. As for Jeans try regular not baggy or skinny and if possible they should look worn add Boots like Chippewa or FRETZ and you are ready to go.