Any tips for a tourist staying in Harlem (214 West 137th street) in September? Do's and don't 's?

We are a couple from the Netherlands staying in a bed and breakfast in New York City in September (9-6 to 9-10. The B&B is located on "214 West 137th street". Since we are influenced by movies etc. we try not to be prejudiced on the area. That would be silly, since over here we also do not walk to our windmill on wooden shoes after putting our finger in the dike to save the tulips from drowning ;-)