I. Get a copy of the Civic Trust model constitution: affiliate also to KFAS.

2. Publicise intentions and invite interested to reply: and/or arrange a 
preliminary meeting with already interested individuals. Spot likely chairman, treasurer, secretary: social secretary, membership secretary, editor, PR/Press officer, planning adviser.
Don't leave anything important to chance or you may be landed with a dud..
Get a friendly solicitor if you can.
Don't ask for volunteers to fill vacancies. (I speak from heartfelt experience).
Choose a meeting place as central as possible.
A Social Secretary is essential: to get numbers you must organise a programme of meetings with able and informed speakers, outings, newsletters.

3. Think which local bigwigs should be invited to be President and Vice-Presidents.

4.  Arrange an Inaugural Meeting to go through the formalities of election, etc. 
Invite press and TV;
Get a brilliant speaker to address the meeting after serving interval refreshments
including a glass of wine, nibbles and cheese.