Your creative should (generally speaking) be set in a very short time frame. The best creatives investigate a moment, or a few vignettes within a short time span. It's tough to say precisely how you want to end a story without knowing the specifics of it, but here are some guidelines:
- Don't be dramatic; if it has any resolution, it should be small and meaningful. A character arc is great, but only if it's believable.
- Endings are not a time for exposition. They should "say" everything through imagery, and relatively clean/sparse imagery at that.
(i.e. don't tell me your character has discovered a renewed interest of life. have them them admire the way the way a moth clings to their bed lamp at night, or recharacterise a motif or image used earlier in the piece in a positive light).
- Be unexpected! - maybe have a discovery be introspective, when they've been seeking external thrills and validation up until then.
- It should link as explicitly as possible to any stimulus you've been given
- A little pathetic fallacy is often under-appreciated