You call the local bar association or law firm, tell them your situation, find the person in charge, and ask them to recommend the law firm where you practice. The law firm they recommend has a good relationship with them, and it will be more convenient when you become a regular.
The law firm you are looking for is not necessarily an internship base. You can't get into a good big law firm because you don't meet their requirements. So try to recommend to these institutions.