Blue Jays like fruit, like black cherry, mulberry (plant a red mulberry if you go this route), blueberry, grape, and serviceberry. They like wooded edges and suburban settings. In the spring they, like most birds, raise their young on caterpillars, so plant some butterfly host plants. Native oak, birch, cherry, pine, apple, and maple trees are all good caterpillar hosts. Goldenrods, asters, eupatoriums, and wild strawberry are decent herbaceous host plants. Planting their preferred plants would be good although it wont be an instant fix, and you will also attract other larger critters interested in the fruit. All the birds enjoy sunflower seeds more than anything at my place. I mix the meal worms in with sunflower seeds but the birds dont really like them and I see them all over the ground around the feeder. Put your feeder near cover, like overhanging tree branches.