Choose a Design Pattern

I need to solve this design problem:

SITUATION:
[Describe the problem you're trying to solve]

CURRENT APPROACH:
[How it's done now, or "starting fresh"]

PAIN POINTS:
- [Issue 1]
- [Issue 2]

CONSTRAINTS:
- [Constraint 1]
- [Constraint 2]

What design patterns might help? For each:
1. How would it apply to my situation?
2. What's the implementation look like?
3. What are the tradeoffs?
4. When would it NOT be the right choice?