Idea: Make posters with the help of pro shops

Many specialist photo-lab shops now offer extra-large custom prints made on wide-format inkjet printers. (Before inkjet technology, it was a little more difficult and more costly to get a poster print (50 cm by 75 cm). You had to send off a negative to an outside processor to make a silver halide print.)
Make posters of your best prints and sell. Or offer a service where you organise for people's digital photos to be made into posters.

This tip is inspired by an article in The Age newspaper