The FRONTIERS project brings together expertise from the fields of Particle Physics, Gravitational Wave Astronomy, Astrophysics, Cosmology and Astroparticle Physics, Science Education and Teacher Training in order to facilitate the introduction of frontier Physics in K12 education. To achieve this goal, the FRONTIERS consortium propose a set of 25 best outreach practices, which can be used as a source of inspiration, in order to create a series of innovative educational scenarios which follow a proposed pedagogical framework: the FRONTIERS demonstrators. These best outreach practices have been identified using a set of quality criteria. Intellectual Output 1 presents: a presentation of the best practices evaluation criteria (Section 1), an overview of the selected best outreach practices with analysis (Section 2), a presentation of the analysis regarding the overall and individual characteristics of the proposed practices (Section 3) and the final conclusions and future outlook regarding the connection of the proposed practices with the FRONTIERS demonstrators. The latter will be discussed in Output 2.