For building grain bills I always reference "Designing Great Beers" Ray Daniels. Great book although I would get some good proven recipes and get your brewing skills up to par before diving into recipe creation.
+1 Designing Great Beers for learning recipe design. BCS has award wining recipes and gives great tips on how to brew specific styles. But Designing introduces some really cool concepts regarding grain bills, hopping schedules, and Bitterness:Gravity ratios all the while referencing 2nd round winning beers at the NHC. Designing may not give you the best guide to winning competitions these days as certain categories creep into bigger beers. But the basic concepts for recipe design are sound.