Short of cosmetic, reconstructive surgery, there's not really much you can do. There are no magic pills – drugs or herbal – that are going to do it for you. Any of these that have any actual safe effects just promote effective blood flow within the penis, which is what's responsible for causing an erection. Increasing the bloodflow safely in the penis will allow the fullest erection you can physically have, or might prolong erection. But you can't get a bigger penis in this way safely.
Men who wish they had more stamina in the bedroom sometimes reach for male enhancement products. These products come in a liquid form and a tablet form that help men struggling with a healthy sex life. Choosing sexual enhancement tablets is a rough task because there are so many different types of products sold under this name. Walgreens.com offers male enhancement products from well-known brands as ExtenZe and Enzyte.