Credibility and being properly heard is extremely important to anyone who is giving talks or is trying to relay important messages. There are several key factors which come into play when you want to appear the most credible during a presentation. Some of the mistakes people make include smiling too much. This may make your audience think that you are not being genuine or you are being fake and will lose them quickly.
Another pitfall one can make it being entirely too energetic. Energy is good, but you must not overwhelm people or they may tune out from your talk. Another thing you can avoid is winking during presentations, it makes people believe that you are not being fully transparent about your topic. You should also look to keep your pace as stable as possible. Speeding up or slowing down too much can cause confusion and lose your credibility.
You should also watch your body language. Things like fidgeting can take away attention from your actual talk and divert it into whatever it is what your body is doing. Like being too energetic, being too stoic or quiet can also have detrimental effects. You want to find a middle ground when you present. Lastly, you want to keep your voice pitch stable, not going too high or too low when delivering important points.