CRM out of the box isn't necessarily as perfect a match to most businesses as it could be. Many a partner has their own "I always do this" at most client sites.
Here are a few of the ones I do.
1) I usually talk with the customer about SOURCE and add a SOURCE Description field. Why?
Well SOURCE is a pick list defaulted on the lead record. The source field needs to be populated through SETTINGS and is not usually updated on the fly. Needless to say SOURCE Description can be used to expand on a picklist item. The Source picklist could be TRADE SHOW and the Source description can easily support the detailed name of the trade show.
2) I usually add a mapping from LEAD SOURCE and SOURCE DESCRIPTION to CONTACT SOURCE and SOURCE DESCRIPTION.
Most firms want to see this source on a flowing and ongoing basis.
3) NOTES Now this is a bit of a personal preference and ties to security protocol, but many firms like to see the notes at the bottom of the Contact screen as opposed to on it's own tab.
4) Move Required Fields (you know the RED ONES) to the first tab.
Of course this increases the chance of users not using any of the other tabs, but it is a balance and a good thing to discuss.
5) VIEWs - Add a few Public views that match the customers current spreadsheets in use and teach a few different people at the customer site how to use Advanced Find to setup their own views.
The Power of the system really comes down to getting information OUT! In fact sometimes we go so far as to setup a few Dynamics Excel Spreadsheets :)
6) Share the USING MICROSOFT CRM website. Clients really do want to do their own studying and research with regards to the art of the possible. http://www.microsoft.com/dynamics/crm/USING