Among the many works on trust negotiation, only a few deal with negotiation strategies. These works are tailored to specific frameworks--so their results cannot be extended to competing approaches--and introduce assumptions that cannot be always guaranteed. In this paper we identify some guidelines for designing "good" (interoperable) trust negotiation strategies under a different set of assumptions, namely, a peer?s interest in making transactions succeed. Moreover, since our analysis is based on an abstract framework, the guidelines apply to a wide range of policy languages and negotiation frameworks.