Fetching details from the dictionary...

to clasp; to grasp; to grip; to clutch
to hold (the answer); to have (e.g. the solution); to be the key; to be the reason
to seize (power); to hold (the reins); to dominate; to control
to make (nigirizushi, rice ball, etc.); to form (with one's hands); to press into shape; to mold; to mould
別れ際に彼の手を固く握りました。
I grasped his hand firmly.
チャンスを握ることができた。
I was able to seize the opportunity.
ハンドルをしっかり握ってください。
Please grip the handle firmly.