What size should wireframe be?
1024×768 pixels for desktop and tablet and 320 × 480 for mobile are generally safe resolutions to work with. Anything higher can be risky to begin with. It is prudent to start with a low resolution and then scale up so that the design still looks adequate when the window is larger.
What is the most important thing on a wireframe?
Your wireframe should clearly display your highest priority content, drive users towards important actions, and help users find what they need. Refining your content structure is the most important goal of the wireframing stage, which is why you should keep your wireframes simple.