I agree it all depends on where you are.
And if you have any skill/passion?
Some freinds paint (some ven sell), are taking parts in photo books publications (usually selling for charities), write, set up scottish dancing classes, baby singing, toddler groups, second hand shops in their huge house (profit goes to charities so no need for permits).... Organised parties, cooking lessons, flower arrangements...
If you are qulaified you can do hairdressing at home, massage, aromatherapy, yoga, pilates.... Be a doula?
support english students
Set up a blog: help for expats, you ups and down.... tips for living where you are, philosophy...
Do you like photography? you can aim at doing a small book of "wonders" of your new place.
Contact your ambassy or the british council, they usually have a list of libraries, charities, language lessons, expats groups,
Same with cultural centers or institutes.
I concur with the yoga!
Any kind of lessons you can take will help you meet people. (even if you don't speack the language for sports) I did aerobic in japanese not that difficult to follow
What about your children school? may be they need help (I know some mums who have a part time job through that route, teaching or admin)
You can google expat + your town (or country) and see if there is anythig already organised.
A huge number of them do help their husband at work though, PR... Not the best route (usually unpaid slave, some paid at the local rate, and it doesn't make them and their couple happy IYSWIM, but as a last resort..