To maximize the vertical space for this drawing, work in the Visio window to reposition the built-in title to the lower right.
You may also need to adjust the drawing's title and position on the slide.
If there's a title placeholder on your slide but you're using a title that's built into the embedded drawing, delete the title placeholder on the slide (just click the placeholder's edge to select it, and press DELETE). Or, apply a blank layout. You can also reposition the built-in title while working in the Visio window.
If, on the other hand, you want to get rid of the drawing's built-in title, open it in the Visio window, select the title, and press DELETE.
If you want to add caption-like text for a title, use the Text Box button on the Drawing toolbar.
If you insert the embedded drawing onto a slide with several placeholders (for other objects or pictures, or for text), PowerPoint should position the drawing so that it fits neatly with the other elements on the slide. If you insert the drawing and then apply a different layout, the drawing doesn't always get positioned as you'd expect. In any case, there's a fair chance you'll have to reposition it.
To center the drawing on the slide, use the Draw menu's Align or Distribute commands (Drawing toolbar). Note that you can center a drawing relative to the slide (you'll see how in the practice session). To move the drawing, rest the pointer over it until the pointer becomes a four-headed arrow . Then drag the drawing into position.