Smidgen. = A very small amount
I take my coffee with cream and a smidgen of sugar.
Petty = Small, minor or unimportant
People who worry about petty matters often end up with a nervous break down.
Good-natured = To have a cheerful disposition, a happy person who is seldom angry
Ichiro is a good-natured person as he usually smiles and angers slowly.
Flaw = A crack or defect.
The bridge in America collapsed due to a flaw in the engineering.
Jam = To block by crowding.
During summer vacation the roads are jammed with people returning to their hometown.
To sleep like a log = To sleep very deeply.
Even though it's very hot I am able to sleep like a log.
Stern = Strict or severe
My father was very stern in regard to punctuality.
To rattle one's cage = To make someone upset
The employee rattled his president's cage by asking for a raise.
To be helpful = Useful
When I first came to Japan a Japanese-English conversation dictionary was extremely helpful.
To set up = To start or to install
I set up this school in 1986 and I've been happy ever since.