Hey, Joan, if you're not seeing enough bookkeeping, tax planning, whatever to take you through the year but are getting lots of calls for tax preparation, then put people on extension to take as many tax clients as possible. You can prepare a lot more returns in 12 months than you can in three. New clients where you need to review past issues, complex clients needing research, clients who come in after 15 March, any criteria you choose. Offer them a discount if they'll go on extension if you have to. Most effective if they don't owe and aren't in a hurry for what looks like a small refund or seem disorganized, would take up a lot of your time, need hand-holding, are already bringing in info in drips and drabs, etc. Save your most time-consuming returns for later so you can prepare as many as possible now.
My first year, learning new software, I offered discounts to some of my nicer clients who followed me if they'd go on extension. Only one preferred their return by 15 April.