I got together with Irene Towers (who'd I met when she was an doing astronomy talk at the Newcastle branch of The Store) and she befriended me (she's a nice lady) and encouraged me to follow through when I suggested to her that maybe there should be local club, as the BAA was not doing it for either of us , so I asked dad to pay for a series of adverts in the Newcastle Herald (I was 14 so I had no money of my own) . Matty Morel , George Elliot and Mrs Towers and I formed what eventually became The Astronomical Society of the Hunter and our first get together was at my home.
For the first year or two we met at each others houses (bring a plate style) , bringing spouses if we had them , and this was done on a rotation , eventually we become affiliated with Newcastle Tech College and started meeting there on a monthly basis.
If a kid of 14 can start a club , anyone can do it . Would be even easier now to get the word out than it was in the 1970s (no internet then).
My advice , keep it very informal , friendly , and unstructured as long as possible , and when you find people who are interested ask them to bring a plate or something (bikkies, a cake, cold cuts etc) , and maybe a folding chair) when the come along to check out the group , so the person who is hosting the get-together (at their home) isn't out of pocket more than brewing some tea or providing cordial for people to drink.
If you meet at night , ask them to bring their telescope , and set your's up too , and ask them to bring their spouse and kid too , to make it an enjoyable family orientated gathering.
Most important is to not be judgemental about other's (lack of) knowledge and gear when you form a club.
Also when the club starts making decisions on things they want to do , make sure everyone who is present at the meeting gets to vote on it. KEEP IT INCLUSIVE and AVOID FORMATION OF AN ELITE.