Well before your first session, you'll want to set up and test your set up - this include both the equipment you'll be using (computer, device, camera, microphone, headphones, etc.) and the software (webinar tool, recording software, content authoring software, etc.).
There's no magic combination but in general, for a synchronous session, you're looking for an HD webcam and an external microphone (while some built in cameras are high quality - especially in newer devices - a general rule is that built-in microphones still leave something to be desired). Turning on your webcam while moderating/leading a session helps to build a connection with those attending (see building instructor presence).
For an alternate opinion on set up, check out Echo Rivera's blog on recommended tools and equipment. This is an external site that provides some interesting commentary on how to select your hardware for both video recording and webinar sessions.