I am hopeless in regards to lore stuff.  On one hand when doing sandboxes lore is just something you'd think you should just make up on the way but than I make a 10 page history on the slug people who conquered the Galaxy a million years ago and I don't know what went wrong.

Lore I suppose with RP is best left simple since every time I try to show all the lore in my RP attempts most tend to vanish.  A few guidelines to enforce creativity (so people don't just make soda colored humans in a Sci-fi RP or make tech that breaks the balance) seems to help.  What sucks for me is that all the species I make are alien in nature so it can be tedious summarizing them in a way that aquedately explains their world view, culture(s) and biology.

I also find it a bit annoying if the lore goes to waste in short lived RPs.  It's the thing that actually eroded a lot of enthusiasm I've had in RPs since I have a bad habit of bottom-up world building and a tendency to build things in terms of first cause.  I can't even NRP in space much more because of this, too many Independant technological origins.  It drives me insane.

Perhaps another guideline to follow is to not go deep in lore unless the core group is entrenched enough that growing the lore may actually give growth to story telling.  Like if the RP's lifespan exceeds one month.