A soccer mom is someone who can't get a job because she has to take her kids to all their activities. While they are at school, she will often help out there too, when she is not 'running errands'.
She's a glorified taxi driver, who bakes cookies every so often.
She might organise the end of season party, but then should would be the 'team mom'. The 'team mom' also rings around if practice is cancelled, and organises the whip round for the coaches' gifts.
As far as style is concerned, practical is key. Flat boots or sneakers, with confortable clothing (exercise gear, sometimes, and definitely khaki shorts in summer). She will have a good 3 in 1 'parka'.
She will shout 'hustle' at her kids, whether it is to encourage them on the sports field or to get them to get their backsides into the car, pronto.