2) Go door to door offering to mow/weed eat/hedge trim with the home owners own equipment. Might have to do this on the cheap since you are using their gear.
I wish that knock would come on my door!!
Also, if you have a smartphone, look at square. Then you can get payment by CC....even easier to get paid. No more "gee, we said $20, but I only have $15 on me...".