With which Design Pattern would you recommend I start?

I guess I started with the following (may not be in order though) and it  was accidental but was definitely helpful and am sticking to these common patterns in my everyday application development....

- Singleton (one instance -> global point of access)
- Factory Method (Use generic factory if you are working with .net to create configurable types)
- Strategy (if you need to vary your algorithms at runtime  e.g. sorting->quicksort->or->mergesort->or some other sorting logic)
- Decorator (attach additional responsibility to an object)
- Facade (Provide higher level of abstraction)
- Command (for eg. for menu actions and toolbar actions)
- Template Method (for what it says... for templated methods that has predefined set of execution cycle like the asp.net page life cycle for eg.)
- And then pick up the ones you understand or could related to in your real work or project work environment.

Hope this helps!.