Meanings of phrases

all thumbs

If someone says you are all thumbs they mean you have no mechanical ability.

hat in hand

Hat in hand refers to someone asking or begging for something as in "I come hat in hand looking for help".

twiddling your thumbs

If you have nothing to do while waiting for something you might try twiddling or moving your thumbs in a circular motion to help pass the time.

hanging by one's fingurenails

If payday is Friday and you have ten dollars in your pocket then you must hang by your fingernails till you cash your paycheck.

hand in hand

Bill Gates might say that the Windows operating system goes hand in hand with the Pentium processor. Hand in hand means that 2 things work well with each other.

by hand

A carpenter made a piece of furniture entirely by hand. To do something by hand means not to use a tool.

hands down

If you really know a lot about something you are described as knowing that something hands down.
Someone who is an expert at something is said to know that subject hands down.

all hands on deck

All hands on deck is a sailing term and the hands are the crewmembers of that ship.
The captain will ask that all hands be on deck to scrub and clean the ship.