Dress for a Lasting Impression
People come in different shapes and sizes.You can improve how you look by dressing up well and grooming yourself carefully. Business causal or smart casual attire, that is not too formal, but at the same time looks nice is recommended for speed dating events.
For men, wearing a full suit might not be necessary,but a dress shirt with nice pants and a smart blazer will do the trick. Women can wear a nice dress and pair with comfortable footwear. If you are comfortable with your outfit and feel good about how you look, that would naturally give you more confidence. This would do half the job for you.