For the best performance, you should try to attach it externally to gear (rather than inside of any gear) and try to elevate the device as much as possible. Even wearing goTenna at shoulder-height rather than at the hip can increase performance by as much as 30%.
For instance, attaching goTenna to the loop at the top of your backpack is better than placing it anywhere inside your backpack. Similarly, in your chest pocket is better than attached to your belt loop.
Also note that goTenna is not designed to be held in your hand; in fact, doing so could noticeably decrease your range. (That being said, if you want to hold it up for more height, hold it from the nylon strap, avoiding touching the metal and plastic casing, as your body can attenuate goTenna’s signal.)