The Ojai Valley Inn & Spa is ramping up its marketing and offering a host of deals to lure vacationers during crucial mid-week nights. Like the rest of the hospitality industry, the high-end resort is fighting for a slice of a shrinking pie. Tri-county tourism promises to be one of the few bright spots in a down economy, but it has become “more difficult to grab market share, so we’ve put together a very aggressive advertising program,” said Peter Bowen, the resort’s sales and marketing director.