In Fascinate: Your 7 Triggers to Persuasion and Captivation, Sally Hogshead tells us that  the following triggers lead to reader-engagement:

1. LUST creates craving for sensory pleasure.
2. MYSTIQUE lures with unanswered questions.
3. ALARM threatens with negative consequences.
4. PRESTIGE earns respect through symbols of achievement.
5. POWER commands and controls.
6. VICE tempts with “forbidden fruit,” causing us to rebel against norms.
7. TRUST comforts us with certainty and reliability.

I’m not sure how you might use these in your portfolio, well building trust through demonstrating consistent competence matters. Perhaps you might use some kind of mystique hook on your first screen. Anyway, some ideas worth thinking about. The link above takes you to excerpts from the book.