table users
id|user_id|fname|.....

table ratings
id|user_id|location_id|rating|.....

Like that, joined on user_id? Users would have multiple rows in ratings. You could do a sum or display individual ratings for each location.

would i make user_id primary key on both tables?

i want the user to be able to rate the place as many times as they like.

DB structure aside, this sounds like a recipe for spamming your site.

would i make user_id primary key on both tables?

No, in the example given above, id is the primary key in both tables and user_id is a foreign key in the ratings table.
However personally I would make the ID fields a bit more distinct and not have two different id fields in the user table as below.

table User
User_ID|Firstname|.....

table Rating
Rating_ID|User_ID|Location_ID|Rating|.....