First you might want to use natural material that you can easily find in your local area. Things such as woods or stone can easily be applied everywhere around the kitchen. This material will help to bring in the nature into the kitchen which also one of the reasons why people love to use this style.
Even though you can use any types of wood in your kitchen, but you might want to try to use rustic wood for your material. This is a type of recycled wood which is great to use since it matches well with the rustic kitchen style that you want to create. Furthermore, using this type of wood is actually more environmentally friendly, thus you can contribute something for the nature.
Try to apply the theme into your architecture if you really want to create something more authentic. For example, try to expose your house beam and use wooden material as the beam. This will make the kitchen appear more beautiful with the beam visible. And do not forget that you can always create faux beam by adding the woods into the ceiling without the beam actually supporting the ceiling.
Another thing if you want to have comfortable old kitchen is to make sure that the kitchen has enough lights. It would be best if it is natural light, thus when you create rustic kitchen style ides try to have windows and opening to let more lights.
image source : pinterest.com