get a grip, get(come) to grips with

9. PHRASE : V inflects

If you get a grip on yourself, you make an effort to control or improve your behaviour or work.

8. PHRASE : V inflects, PHR n

If you get to grips with a problem or if you come to grips with it, you consider it seriously, and start taking action to deal with it.

• The government's first task is to get to grips with the economy.
  

.... Cobuild

get a grip (on something): to understand how to deal with something.

• The program will have helpful tips on how to get a grip on your finances. 
• Something is obviously not right in our organization, and we must get a grip on the problem.
  

get a grip (on yourself) (spoken): to control your emotions. 

• I know it's hard, but get a grip on yourself and tell me what you saw. 
• Oh, get a grip, Tess! It's really not as bad as you think.
  

... Cambridge-Am-Idioms, http://idioms.thefreedictionary.com/Get+a+Grip

come to grips with someone or something: 

Fig. to begin to deal with someone or something difficult or challenging in a sensible way. 

• We must all come to grips with this tragedy. 
• I cannot come to grips with Ed and his problems.
  

... McGrow-Hill-Am-Idioms

to make an effort to understand and deal with a problem or situation 

• The whole community is struggling to come to grips with these kids' deaths.
  

...Cambridge-Am-Idioms

cf.

"Most of the unique features of the modern human hand, including the thumb, can be related to... the stresses that would have been incurred with the use of these grips in the manipulation of stone tools."[*] Thinking then ensues about the nature of what one holds. American slang advises us to "get a grip"; more generally we speak of "coming to grips with an issue." Both figures reflect the evolutionary dialogue between the hand and the head.

[*] Mary Marzke, “Evolutionary Development of the Human Thumb,” in ^Hand Clinics^ 8, no. 1 (February 1992)