I started potty training DD1 about 6 weeks ago, she is now 2, and it went a bit like this:
Day 1 - no nappy or pants, told her she needs to do her wees in the potty, reminded her every half hour or so, had a couple of accidents but she got a wee in the potty, lots of cheering, clapping etc. stayed in, (i started in the afternoon so just a half day)
Day 2 - much of the same, nappy off as soon as she got up, one or two accidents but she seemed to have the hang of it, still stayed in.
Since then she has been fairly consistant, doesn't need reminding to use the potty, and wears pull-ups in bed and when we go out. she understands that if she doesn't have a nappy then she has to use the potty, and has recently started being able to take her "big girls pants" off by herself to have a wee. its easier in the early days to leave them naked from the waist down.
I find pull-ups easier when out because you don't have to stress about being near a toilet or taking a potty with you, once DD is a bit older and can hold it in longer then i will stop using pull-ups.
i found it best to be very blase about accidents "oh well, next time try and do it in the potty" sort of thing, the more relaxed you are then the more relaxed you DS will be.