I use to not do any lip slurs or flexibilites exceries. Then my teacher recomeded some lip slur exceries. My playing improved a lot. Particurly in the range deparment. Once you get to the advance stage's of flexibilite I recomend patrick hession's book "For the sake of lead trumpet playing - Hessions Sessions Guide to consistent, reliable and sometimes, Invincible Chops!" This has some good lip slur exceries in it. Here a link to buy it. http://www.hessionssessions.com/products.html I would not try this book untill your chop's are develed enough to hand it. There is alway's good advice on TM, use it!