I would agree with @robkk, those links are worth a try. You can actually decide what works for you best by checking thier active instals and ratings by users. Then you can have a look at the screenshots to decide if that is what you would like to go with. I feel its better to go with somethings that has been developed already, tried and tested by users then tryin to build something fresh.
My choice from the lot (as mentioned by @rorkk):
https://wordpress.org/plugins/wp-postratings/
