10-15 pages for an entry portfolio? Some suggestions:
• 1 or 2 on illustration
• 1 or 2 on 3D work like mock packaging
• 1 or 2 with some animation or storyboarding, showing the ability to think in timelines
• 2 on drawing; general and life drawing
• 2 to 3 involving type, from a layout to some display type
• 1 to 2 on branding, a logo and strapline perhaps, extending it to maybe a mock ad, some stationery or a mock web page
• 1 or 2 on something in a related field, like photography, sculpture or painting... something you have a real passion for