In our public speaking course, the issue of what to wear arises regularly. Here are my thoughts.
Dress appropriately for your audience - don't worry about dress changes during the breaks unless you deliver the Oscars. Even that 'extraordinary' event creates negativity in some fields, given that many people in this world don't have more than one set of decent clothes.
For formal situations, wear a suit. In less formal situations, wear a smart jacket, shirt, trousers and good shoes. Jeans and trainers will attract criticism from some organisations. I worked in Romania over the summer, and some classes were held outside the venue at an outdoor museum. The students were in shorts, and so was I.
I recently attended an event dressed informally, and all of my Executive audience members arrived in suits. (The message from the HR person never got through to them). My opening line to them was, 'I do have a suit,' which got a laugh and broke the ice.
Our public speaking courses and train the trainer courses convey a great deal of conventional wisdom about communication and its surrounding issues. Plus, it's fun and memorable. Give us a call and catch up on best practices.
