Perhaps best known for his immortal (until the next Dark Ages at least) characters Jeeves and Wooster, P.G.Wodehouse took the art of descriptive prose to new ...new... new ... damn, I need to begin reading his work.
The (words in brackets) after each quote refer to the book in which it appeared. Most of these were picked from the ones picked by Colin Jarman in his excellent "Guiness Books of Yet More Poisonous Quotes".
His IQ was somewhat lower than that of a backward clam -- a clam, et us say, which had been dropped on its head as a baby. (Barmy in Wonderland)
He was a small man with the face of an untrustworthy monkey, the sort of monkey other monkeys would have shrunk from allowing to come within arm's reach of their nut ration. (Money in the Bank)
He looked like a pterodactyl with a secret sorrow. (Mulliner Knights)
Her mouth had the coldly forbidding look of the closed door of a subway express when you have just missed the train.
A small shrivelled chap. Looks like a haddock with lung trouble.
He looked like a halibut which had been asked by another halibut to lend it a quid till next Wednesday.
If ever there was a pot-bellied little human louse who needed to have the stuffing knocked out of him and have his remains jumped on by strong men in hobnailed boots, it is you. (Uncle Fred in Springtime)
As ugly a devil as you would wish to see outside the House of Commons.
Too many cooks, in baking rock cakes, get misled by the word `rock'. (Money in the Bank)