Lying on the floor with your elbows propping you up, place the foam roller under one of your thighs just above your knee.
Focusing on just the first few inches up from your knee, roll up and down on the roller. You are using your opposite knee to support you and help with the movement.
Make sure that, whilst moving up and down that you also adjust your body so that the roller works on the muscles of the inside and outside of your thigh.
You are doing this for 2 reasons. Firstly you are warming the muscles up and secondly you are looking for any areas that are either particularly sore or feel restricted in any way (the more you do this the more you will understand what I mean).
When you find an area that needs some more attention, spend a little time there rocking side to side over the area so that you end up moving ACROSS the muscles.
You can also spend time bending and straightening the knee whilst applying a maintained pressure to the target area (you won't need to roll…stay still and JUST move the knee).
When you have worked on the first few inches then move the roller up a little and work on the next few inches following the same principles as above.