Every time I print handouts of my presentation, PowerPoint always leaves large unnecessary white space around the individual slide. This is a predetermined setting, which is quite annoying.
Here is one simple tip to reduce the margins of the handout and enlarge the slide images:
In the PowerPoint, Print -> "Print What" choose "Slides"-> OK
For example, print it to "single_slide.pdf"
Open the "single_slide.pdf" in Adobe Acrobat or any other pdf viewer.
File -> Print -> Properties -> Layout -> "Pages Per Sheet" -> choose the number of slides you want on each page -> OK
For example, print it to "double_slides.pdf"
Here you go, now you can have a handout with smaller margin in the "double_slides.pdf".