While presenting during a call or during a webinar you should also think about the sound quality. The quality of the sound is important for those who are listening to the conference call or webinar. Bad sound quality is easily to be associated by bad quality of your presentation.
Use a high quality microphone. Maybe you can take advantage of a quality podcast microphone that you can connect to your computer. Usually dedicated microphones have better quality compared to the microphone in your computer.
Also think about the room where you are to present from. Clap your hands and listen if there is an echo. Having an echo should while you are talking also doesn’t sound very professional. Consider changing to present from a different location where there is less or no echo. You can also take some measures to reduce the echo. For example by using surrounding yourself with materials that absorb the sound, such as linen, hanging cloths, fabric, close the curtains, etc.