Here's another useful link with tips about EF, written by on of the program managers.
Most of the tips revolve about EF today, some of them are related to the upcoming release.
Just to give you an idea, here are the latest tips:
Tip 26 – How to avoid database queries using Stub Entities
Tip 25 – How to Get Entities by key the easy way
Tip 24 – How to get the ObjectContext from an Entity
Tip 23 – How to fake Enums in EF 4
Tip 22 - How to make Include really Include