The IETF's mission is "to make the Internet work better," but it is the Internet Engineering Task Force, so this means: make the Internet work better from an engineering point of view. We try to avoid policy and business questions, as much as possible. Most participants in the IETF are engineers with knowledge of networking protocols and software. Many of them know a lot about networking hardware too.
The IETF's standards development work is organized into several Areas. Each Area has one or more Area Directors (ADs), which together comprise the Internet Engineering Steering Group (IESG). The IESG is responsible for technical management of IETF activities, the Internet standards process, and for the actions associated with entry into and movement along the Internet "standards track," including final approval of specifications as Internet Standards and publication as an RFC.
Within each Area there are multiple Working Groups (WG). Each WG has one or more chairs who manage the work, and a written charter defining what the work is and when it is due. There are more than 100 WGs. The WGs produce Internet Drafts (I-Ds) which often lead to the publication of an Internet standard as an RFC. The IETF Datatracker has the charters, chairs and other information for all the current WGs.
People interested in particular technical issues join the mailing list of a WG (also available via the IETF Datatracker) and occasionally participate in IETF meetings.