Sex with niece

If you're really looking for advice you need to let us know some details about yourself and her. Leaving the new both your physical attributes and your age ranges.

Alcohol and cheap gas station pills.

The right drugs and she'll let you do whatever you want. Works on daughters too!

Get her alone. Compliment her on her looks. Buy her things. Take her places. Get a hotel room and only ask for one bed that way she will have to share the bed with you. Sleep naked next to her.
If it all fails, force her.

Is she old enough?