How can I avoid getting migranes, n is my presymptoms normal: I get blury vision, left hand goes numb. And what is best med. To take?

Atypical migraine. Your description sounds like an atypical migraine. Standard migraine therapy should control your symptoms. You should see an eye doctor for a complete eye exam and to confirm proper diagnosis and initiate appropriate treatment.
See neurologist. You first need to make sure it is not something else. If it truly isi migraines there are medications such as beta blockers that prevent attacks.