If you really suck at it, i would suggest you do like a circuit, choose a whole bunch of stretches do them all in a row holding for a minute, then repeat the entire circuit @ least once, specially on winter time. One more thing about them, whe you stretch a muscle the antagonist muscle must be be relaxed or else that excessive and unnecessary stress, say you wanna strech the hammstring... your quads and knees must be relaxed, that's much safer and productive.