Forming a coalition government requires knowing and evaluating the elements that condition the negotiating scenario, exploring the different parties’ proposals and the best formula for achieving them, applying equitable criteria in the distribution of power, and establishing certain guidelines for internal functioning. This guide—aimed at political parties, representatives and advisors, as well as social actors—presents the mechanisms used to successfully achieve these objectives, detailing the different phases of negotiation and outlining a systematized set of practical indications for their formalization. Governing in coalition requires a great deal of effort on the part of those involved, but it undoubtedly strengthens the democratic values of dialogue, trust, agreement, tolerance, solidarity, and civic-mindedness.