like Katrina said, wait until they're 5 mins apart.
Real contractions will NOT let up, no matter what position you get into.
Also, they radiate. Either from the back to the front, or vice versa.
You'll DEF know when they become "regular" and more intense. THAT'S when you need to leave for the hospital.
Don't wait for your water to break. Mine was broken accidentally at 8cm when I was being checked!
Good luck, and i hope you're labor is smooth and easy!
Sarah