I think the best way to gain girth is with a penis pump. I use a water based penis pump myself. Here is a before and after picture I took
(sorry for the website branding guys, as I mentioned once before someone has stolen my pictures before and I dont like my dick being used all over the internet. So instead I started my own website)
That is after one pump using the penomet water based pump. Its a great pump, you can see it
here. You should also always incorporate penis exercises and such into your routine. Its just good practice man, its been proven to help penis health etc...
Also - I know my girth isnt CRAZY, but thats after only one pumping session so I dont think its to bad. What do you think?