Want to decorate like a pro? The big trick is to make whatever you're styling feel like it's always been there.                  Paintings, mirrors and wall sconces turn flat surfaces into something more intriguing. When it comes to styling mantelpieces, shelves and consoles steer away from stuffy and over-considered, and think laidback lair.           Prop up your art for that cool bohemian vibe. Up the verticals. By which I mean, elongate the space by displaying something tall, like picture frames, flowers or plants. No matter how high or low your ceilings, it ups the impact.