Like CaramelHonee and ArmyQT said, comb the hair in the opposite direction you're rolling and make sure you keep it in that position as you roll back towards your scalp so you can keep the tension on the hair. Sometimes it's hard to keep the tension on the hair when you're reaching behind your head and your arms get tired. If you picture the open end of a roller as a clock, I try to place the clip between 4 and 5'o clock, which is right behind the roots like ArmyQT said. The rollers in the front are the hardest for me to get tight, so sometimes I do clip them together.