Table 1 ItFits-toolkit mechanisms and guiding principles

M1. Non-standardised, systematically guided step-by-step process

M2. Stakeholder-based co-creation of solutions

M3. Tools to identify local barriers, consult stakeholders, and match to suitable strategies

M4. Evidence-informed materials on barriers, strategies, and intervention planning

M6. Six guiding principles

P1: Be pragmatic—Focus on realistic, achievable, next steps

P2: Be focused—Focus on one thing at a time, don't try to do everything at once

P3: Be different—Do not only focus on things that you feel most comfortable with or the things you would normally do

P4: Be open—Listen to and value your stakeholders’ knowledge and experience

P5: Be organised—Each step needs an identified owner to take responsibility for delivery

P6: Be flexible—The same solution may not work for everyone, so be prepared to adapt your plans and ideas