I'm a busy mother of some very active little ones as I know a number of women are. It can be challenging to stay motivated to dress well when all you're finding yourself doing is the daily carpool, play dates and grocery shopping. But on the days that you find yourself on these errands and you don't know how to be practical and still stylish at the same time here is what I have to say...
It's really not hard or time consuming to make a t-shirt and jeans look purposeful and still incorporate your own personal style, which is what I think is the most important part- I suggest just adding one accessory that pops to finish it off.
Possibly a scarf, trendy head band, colored belt, long necklace or some eye catching flats. Don't over-do it and don't try to be too matchy-matchy. The goal is to make it look easy and not over-thought.
Even just remembering to grab one of these items on your way out the door will help you achieve that "I know what I'm doing" look instead of "What has my life become?" look.