De-clutter. Let go of things that are not needed. If you are to live as a minimalist, then your entire surroundings will embrace this philosophy.
The saying "less is more" is important to this type of design philosophy. Your environment will be a reflection of this where your home, office, car, etc... will become an extension of this thought form.
Each piece that you bring into your home will have multiple tasking potential, otherwise, you will not purchase it and bring it into your environment.
Rather than having an entire closet full of clothing, you will select clothing pieces that gain more mileage with multiple uses of wear. The minimalist view on clothing would be similar to the 1980's corporate capsule wardrobe where you can mix and match a few pieces within your wardrobe to come up with multiple ways of wearing something. Rather than having a huge selection of pieces, you will have fewer items that you can mix and match.
Einstein didn't want to waste his time with shopping and having to create a different wardrobe everyday, so he just bought the same exact suit and had multiple suits of the exact same kind. He didn't want to clutter his thinking and pull attention away from his true focus, his work. He simplified even his wardrobe, in order to place more time and focus on what was important to him.