The types of work you should be prepared to contract out are illustrative art, full color magazine quality flyers or posters, and bindery.  Clients for this work include light manufacturing that require assembly or operating instruction that include diagrams, software or product developers that need manuals for their product, and interest groups looking for high quality flyers, posters, or newsletters.  You can still produce their layout and design, arranging for the additional services for them, and retain the image of a full service desktop publishing business.

Too many desktop publishers think in restrictive terms.  An example of what might be declined is a staple bound newsletter with full colored cover.  It is unaffordable to run the covers on an inkjet printer, but if the layout is prepared for web press the printing costs should be more affordable, and the content pages created in-house, with the final assembly being accomplished at your office.  Knowing what the cost of the colored cover will be by having previously networked or contracted a web press company will make quoting the job as easy as an in-house project.

You will have to get accustomed to having a network of printers, cutters, bindery, photographers, illustrative artist, on hand to refer to at any time.  Don't be afraid to take on partners through networking or subcontract, they can greatly add to your business by providing those little details and services you cannot achieve on your own.