Sorry if this is obvious, but try leaving information in:

Tourist information centres
Libraries
Hotels
Bed & breakfasts
Cafes

You need smallish handouts for all these. The Lewes Saturday Folk Club uses a piece of A4 folded in three, printed on both sides.

Try to have posters on display in your venue, particularly where they can be read from the pavement outside.

I've just started sending stuff to the student unions of local universities; it remains to be seen whether they bear fruit, but every university and college had a folk club years ago and there must still be a few students interested.

Valmai