How many times have you washed a shirt only to discover a stain on it after the fact? That phenomenon is the reason my mom required everyone in the house to tie a knot in their stained garments before they put them in the hamper. That way, when you sort the laundry, you instantly know when something needs extra attention. I implemented this rule within my home and it saves me headaches, time, and money!
For those pesky stains, here is a guide of what to use: http://amumntheoven.blogspot.ca/2013/01/tip-of-day-163.html?m=0