“The multitude sank down upon the ground.” As they could not sink up or in any other direction than down, the latter word should be omitted.
Smell of
“Did you smell of the roses?” “No; but I smelled them and found them very fragrant.” “The gardener smelt of them for he has been culling them all morning and his clothing is perfumed with them.” The of is superfluous in such expressions as taste of, feel of, and usually in smell of.
Think for
“He is taller than you think for.” For is unnecessary. “He is taller than you think” is the contracted form of “He is taller than you think he is.”
Differ among themselves
“The authorities differed among themselves.” The words among themselves may be omitted.
End up
“That ends up the business.” Say “that ends (or closes) the business.”
Had have