How should I properly shave my pubic hair?

I'm 14 years old, and it seems like every time I'm in the shower shaving I end up cutting the spot above my penis and sometimes even my penis. It can be very painful and I want to avoid further cuts at all costs. How should I go about properly shaving? By the way, I use a Gillette razor and Gillette shaving cream if that makes a difference in your response. Thank-you!