Tawxic, stop over-analyzing this (nerve-endings, alcohol, etc). The more you focus on it, the more anxious you'll be the next time at bat.

It's happened to everyone.

I go with prolonged foreplay and relaxing. Have some intense and no-time-limited naked play with your girlfriend. Make out, laugh, talk, explore each other's bodies. You'll lose inhibitions and anxiety and really make the whole experience a lot more enjoyable and memorable.