So I finally read Tolkein's The Hobbit, and I thought I'd try my hand at visualizing some of the creatures and characters for myself. I'm trying to approach this with no reference to previous interpretations...
I like the idea of hobbits as fauns - it's not just their feet that are hairy! Also featuring Gollum, Smaug, and a sample elf. The elves in the Rankin-Bass Hobbit movie are pretty weird, but their green skin is cool, so I straight-up stole that idea.
Lots of possibilities for dwarf proportions. I like the idea of big heads and torsos with small limbs, like real-life dwarves, simply because you seldom see this in fantasy illustration.
Gollum and goblin ideas. Really, all these guys should be roughly dwarf- and hobbit-scale. The Great Goblin, as per Tolkein, is distinguished by his exceptionally large head.