To me, this is more important than achieving some particular and predetermined level of participation in the research. They work for me. Renegotiating the relationship I said above that flexibility and responsiveness are important to me. To a large extent, the flexibility in the research is determined by the flexibility in the relationship between researcher and clients. To negotiate your entry to a client group, and to agree on your role and theirs, requires a certain level of communication skill.
Most people have enough for the purpose.
Some don't always make good use of it. There is an extensive literature on communication, much of it practical. In addition, I've also written some material for the archive. If in doubt, tell the truth. Tell it about yourself, and about the client.