Good intervention strategy is a conundrum: It depends whether you see it ex-ante or post ante. Nevertheless, here is a stab at a good intervention strategy, limited to international conflicts, with an intra- or infra-state dynamic:
1.) Conduct joint diagnosis, incl. early warning, conflict analysis, assessment and risk scenarios;
2a.) Decide to freeze, ie. in the event of an escalating conflict, spill over of conflict, mass atrocities or grave human rights situations: contain, initiate mandate at the highest level (check your regional security arrangement framework), initiate peace operations, enable multi-track diplomacy, enable conducive environment for CSO initiatives, establish monitoring and reporting mechanisms;
2b.) Decide to unfreeze, ie in the event of a de-escalating, latent or emergent conflict: make use of quiet diplomacy, upfront civil society, engage in national dialogue, deploy preventive measures, install observatories;
3.) Secure funding (either mission related or bespoke);
4.) Enable local peace agendas (which, in return, neutralize negative forces and shadow actors);
5.) Deploy public diplomacy and enable conflict sensitive journalism;
6.) Install special victims courts to address justice dimension of conflict;
7.) Launch national dialogue structures, with locally rooted ownership, and supported by regional frameworks to channel resources and voices;
8.) Prepare comprehensive peacebuilding agenda (incl. DDR, SSR, HR, etc.) and support existing conflict management structures;
9.) Enable operational conflict management mechanisms, if the resolution of root causes is a long-term objective;
10.) Advocate and support restorative justice and reconciliation efforts, incl. the politics of memory.
Happy to hear your thoughts and to discuss cases.