Tips: Merging Objects
Sometimes, two mods might provide the same object. This is where object merging comes in handy. NullCascade demonstrates the issue quite well in his README for TES3Merge, please check that out for an in-depth look at the topic.
For OpenMW, the most powerful solution to this issue is Delta Plugin by Benjamin Winger. The project README has a detailed description of how the tool works, but from a user's perspective it's a lot like John Melesky's OMWLLF script. The tool's usage notes give detailed instructions on how to use it.