I just finished my first creation with different high and low poly meshes and cannot help thinking that maybe there would have been an easier way to manage it.

I created the high poly mesh first and mapped it. I saved the UV layout. Then I created the low poly mesh from scratch and used the existing high poly mesh to make them same size and mapped the textures to same places that the high poly mesh did by using the saved image of the UV layout as my guide.

I'd love to hear how you create your high poly and low poly meshes and textures to match. What is the best way to create stuff? Is there some easier way to match the UV maps?

I noticed the Blender has a "decimate" modifier that reduces the polycount of the mesh, but I think the mesh was quite a mess after using it.

Another thought that occurred to me was that maybe it might be easier to create the low poly mesh first. Most of the changes in my objects have been possible to do with modifiers and in that case the high poly copy would "inherit" the existing UV mapping from the low poly version.

What is your favorite way of doing the mesh pair?

The one time I made a lod 2 and 3 from a new high poly mesh, I used the method here: http://www.modthesims.info/showthread.php?t=429672 using Milkshape.

My situation was somewhat simplified by the fact that the entire mesh is assigned to one bone - according to the tutorial you'll need to do some work on the bones for upper body meshes at least, but otherwise I found it to produce very good lower poly meshes. Again in my case, I remapped the UV separately for each lod, but I seem to recall that the original UV mapping was retained in the lower lods - can't swear to it, though.

I never took the time to figure it out but i suspect the errors are because lower lods dont use all the hand joints(index01/02/03, thumb01/02/03 etc) as the higher lod does.
For the lowest lod you quickly reassigne everything to the hand joint only, no one will notice at that distance.
The medium lod you might want to fix by attaching a default lod2 hand.

also keep in mind you often have to move vertice arround the knee and elbow to let them bend correct.
direct x does not group them correctly in those areas.

But i haven't found a quicker way yet.