Design for the overlay
Say what will sit on the background and where: 'soft abstract gradient, generous empty space in the center, subtle detail at the edges' for a quote card; 'blurred café interior, clean lower third' for a title slide; 'dark textured surface, gentle vignette' behind a bright product cutout. Backgrounds fail when they compete — 'low contrast, no focal point' are legitimate, useful prompt phrases here, which makes this the one image genre where you ask the model to be boring on purpose.
For text overlays specifically, keep the value range narrow where the text lands: mid-tone busy areas kill both white and black type.
Match your brand palette exactly
Name colors precisely — 'deep navy to warm coral gradient', 'sage green linen texture' — or reference your palette's mood ('muted earth tones'). Generate a batch, pick winners, and reuse the wording as your team's standing background recipe. Consistent background language across decks, social posts, and ads quietly does a lot of brand-building.
Slides, stores, streams, and video calls
Presentation decks get custom section-divider backdrops instead of template gradients; e-commerce teams generate scene backgrounds to composite products into with Remove BG; streamers make branded overlays and starting-soon screens; remote workers generate tasteful video-call backgrounds. One tool, one prompt pattern — 'what sits on top, and where' — covers all of it.