Use the “dependant picklists” feature to reduce it! For instance, if you have a picklist with every country in the world on it, and you want to make it easier to choose a country, than scrolling through 200+ countries, simply create a “Region” picklist with the 3 options: Americas, Europe, and Asia. Then create a 2nd “Countries” picklist, that will only display the North and South America countries if you chose “Americas”.
First create the two pull-lists mentioned above, and then 10 steps are all that is required!
1. Click Setup > Create > Object
2. Click your object.
3. In the Custom Fields & Relationships related list, click Field Dependencies.
4. Click New.
5. For the Controlling Field drop-down list, choose “Region”.
6. For the Dependent field drop-down list, choose “Countries”.
7. Click Continue
8. In the column labeled “Americas”, double click on the countries related. Continue this exercise for Europe and Asia.
9. Click Preview to test.
10. Click Save.
DONE!