Do you work in a local authority?
If you work for a local authority, for example in public health, one of the the best ways you can support divestment is to get involved with existing campaigns to divest local authority pension funds. These campaigns are coordinated by 350.org UK and details of all those that currently exist are available here.
If there is not yet a campaign in your authority then you could think about starting one! Again the above link is a great starting point, or contact us. Local authority campaigns benefit from the support of health professionals, who can speak with authority on the health harms associated with air pollution locally, as well as fossil fuels and climate change.