You can reach projects seeking partners by clicking the Apply for funding - calls link from the Funding & Careers section at ec.europa.eu/research.
You can reach organizations looking for partners via the link for partner search announcements at www.h2020.org.tr.
You can view the previously funded projects from http://cordis.europa.eu/home_en.html and search for Keyword related to your research areas and contact researchers working in the same field.
Information days and common search presentations published on the websites of the project markets can be examined.