Hi, you can hang big pictures first. Big pictures, especially ones you're especially proud of, deserve a prominent position in the room. Hang them at eye-level or higher on a wall where they'll be noticed. Give them priority positioning – a great picture can double as a room's centerpiece. Don't put them too close to any of the room's corners – you'll inadvertently give your art a “squished in” look. A foot or two of room should suffice. check out this link to find more wall hanging decoration ideas.