1) Read 8 Tips for Beating a Claw Machine from Mental_Floss.
2) Watch It's Not You. Claw Machines are Rigged from Vox. (Above)
3) (Optional) If you're still curious, look into/consume more sources of information about claw machines.
4) In the comments below, let us know whether or not you're likely to play a claw machine in the future. Explain why you've chosen to play, or not play, with these machines.