How do you stretch before you exercise?

I am sure this is a Captain Obvious question, but how do you stretch before hand? I am good with after and do it, but before I can barely move a muscle. My muscles that need to be stretched are so tight and just don't bend until I have started the yoga class (for example). Then I warm up and at the middle point of the class I am really bendy and feeling limber. I do a few more poses and then savasana and I am done. I don't stretch enough after it's done as the next day I can barely walk down the stairs. There is no happy medium. I was doing yoga 3x week plus other exercise (treadmill and weights) and never got to the page of not crying out in pain the next day.