The first external element to deal with is what to wear when presenting. When you're not presenting, anything goes, depending on corporate or social standards. You know what you can or can't wear. In front of a group, I suggest you stick to something BASIC: a Believable Appearance is Simple and the Image is Conservative.
Try for that classically conservative look with a dash of personal style. When you dress more conservatively, the audience accepts you more quickly, and you will reduce those first impression biases. A business presentation is contemporary, and your clothing must not overtake the message. A few points to keep in mind to make your clothing go unnoticed are discussed in the following sections.