Sharing your presentation or screen can help effectively convey information to the group, or help stick to the meeting agenda. Using Skype for Business, you should share specific programs (e.g., PowerPoint) rather than your desktop to avoid distracting notifications and to protect any confidential information on your desktop.
Using polls within your online meeting can help with decision making when there are clear choices (e.g. three date/time options for the next meeting) or to check in on attendees' understanding of a finite topic (e.g. asking a question based on previously discussed content). Polling for a question with a correct answer may help the chair determine what needs further emphasis or explanation.
Engaging through video and instant messaging (IM) can add to the experience of some meetings and detract from others. Seeing team or group members' faces can add a sense of accountability and shared purpose. Instant messaging can allow others to add questions to be addressed once the main content pieces are discussed.