I get about a third paying by cheque. When I started out on the windows, a mate told me to use envelopes with address on, no stamp, and it saves going back to collect which can be a waste of time and effort if not in. Great advice. I never go collecting. I let my customers know the set-up from day 1 then either Cash if in or envelope and cheque sent later if out.
I made a new invoice slip out about a year and half ago with a few payment options with the intent of seeing if I could get more customers to pay online!! It worked well. Options were: cheque, online, Pingit.
Now, although I still get a few cheques, many more pay online than a few years ago.