As with everything, the more you do it the more comfortable they get with it. I have been brushing my baby's teeth from the moment they arrived and he actually looks forward to it. I found Orajel has a fluoride-free toothpaste (with Thomas the Tank Engine on it), which is what I have been using.
Mine had six teeth by his first birthday, two below, 4 uppers and is now breaking through four molars (2 upper, 2 lower) - which is interesting because there are still teeth in between that haven't come in, yet.
Just like me. Doin' his own thing!