Use a medical traction device such as the Andro Penis.
This method is based on exerting a gradual tractive force of 600 to 1500 grams to permanently expand the blood-carrying chambers (the largest being the corpus cavernosa) of the penis.
The microcellular result of this traction is an increase in the total number of cells, and the macrocellular result in an increase in the total tissue volume and thus an enlargement of the penis. These are permanent gains.
Use the Andro Penis device 4-9 hours per day for 3-6 months. You will have time-linear flaccid and erect gains in length, and less pronounced gains in girth. The flaccid gains appear first. The first two months' gains are usually very significant because of additional gains from lengthening of the tunica muscle.
I've gained permanently 1.75" length and 1" girth since June 2005 through the use of an Andro Penis medical traction device and PowerJelq for exercises. (You can supplement the traction with manual or PowerJelq exercises which increase blood flow to the penile tissues).
Try the Andro Penis, and you will be happy to see serious gains after 3-6 months usage.