I didn't read all the responses, so if I'm repeating please forgive me...or ignore me :-)
There is a special brush that is made to clean the inside of the dryer vent. It is long and thin. You just slide it down in there, move it side to side to, and pull it out. Clean the bristles off and do it again until you don't get anymore lint. I use mine once a week.
Also, take the hose off the back of the dryer and clean it out. I use my dryer lint brush in the hose, and also run it up into the back of the dryer through the hose connection opening. I was amazed at how much lint was in there! I do that every other month to keep it from building up, but I was told twice a year for that area is enough.