The Opening Parliament blog has seven tips on opening up Parliaments, taken from discussion at Personal Democracy Forum Poland. Most are also relevant to Open Policymaking (hat-tip, too, for Giulio Quaggiotto from UNDP).
I particularly liked:
4. Understanding why citizens engage: Meeting citizens’ expectations for use of PMO websites is important to attracting repeat users. Ostling identified some reasons citizens use PMO websites, including: they receive answers from MPs; they believe PMO information to be trustworthy and neutral; they desire to build support for their priorities/beliefs. As Paul Lenz of mySociety noted in a panel the previous day, citizen engagement is only worthwhile if they get something back.