When I had daughter's I had visions of them always looking nice in perfectly pressed dressed and cute little outfits.  Just one problem - my girls are total tomboys.  They ruin clothes all the time and I feel like I'm always buying new stuff so they look good at school and when we go out. Honestly, they can ruin an outfit the first time that they wear it. They rip things, they stain things, they even manage to lose things!
I've finally figured out some tricks to help them keep their clothes nice.  

~ First, we have three sets of clothes. There are play clothes (which are items that used to be school clothes but aren't nice enough anymore), school clothes, and what we call fancy clothes (the outfits they can only wear under my supervision since the school clothes have a abit of getting ruined after a few wears). 
~I have separate drawers for them so they have their play clothes drawers and their school clothes drawers.  Their "fancy" clothes get hidden in my closet because the are the ones that they seem to like to wear the most! They know which drawers have their school clothes and that is where they go when getting clothes to wear to school each morning. 

~ Making it part of the routine to change out of their good clothes as soon as they get home from school.  Before they even have a snack, they know that they have to change into their play clothes and put their school clothes into the hamper. 

~ I also carry Tide to Go with me everywhere I go! 

We still go through a lot of clothes, but that's just part of having kids. At least now they always have something clean to wear to school and when we have to go somewhere special I always know that I'll find something decent for them to wear.