Complaintline is a website that shows people how to complain effectively about all sorts of things, including legal services. The page link shown here has help and guidance on making a complaint about a solicitor or barrister.
The Law Society of the Australian Capital Territory has produced a leaflet on how to make a complaint against a solicitor. A direct link to the leaflet can be found here.
This is a four page leaflet published by the New South Wales Law Society about how to make a complaint regarding a solicitor.