Leverage your login to showcase your product's core value.
People visit your login page very often. Remind them why your product is so valuable and why they chose you in the first place.
Use the proper visuals and/or testimonial of your most satisfied customers.
Leverage Branding
Leverage your branding to spice up your common (boring) interactions like feature announcements.
Explain Clearly Permissions
Always specify why your app or plugin needs specific permissions from users.
Direct Users With Faces
Use faces to cleverly direct people to your important content.