Hunter69's on the money. Trial and error, personal taste.
Best to brine if you like them moist. Pretty much all meats are brined before smoking - think bacon & ham etc. You can do it rough and simple, dust with salt & herbs etc and then smoke but they will come out a bit more like jerky.
Then there's the type of wood you use too! Redgum seems to be rather popular but i find it too 'harsh'. I prefer fruit (apple, cherry, olive, peach...) or hickory.
One of those small box smokers with the metho burners, i go with an objective 'handful' of sawdust over the hot spot, where