Watch the calorie intake. Maybe not actually calculate it if thats what you want to avoid but trying adding say 250calories to what your eating now. Reassess every 2 weeks rather then each week. If weight hasn't gone up then up it again with another 250calories. You want to find a point in which your weight goes up slowly but your body fat doesn't. Ie measure the smallest point around waist and use that as a measure of fat accumulated. Weight goes up, waist stays the same, then everything working perfectly.
Think terms of months rather then weeks for an overall bulk. It all depends on what you want to look like. You could eat anything not nailed down but then you'd look like crap and your relative strength (weight lifted V's your bodyweight) will decrease as well. You've most likely seen the fat slob in the gym that noone would be able to tell he works out, compare that to the mens fitness or mens health cover model. Bodyfat low, bodyweight also low when compared to a powerlifter or similar.
There are many forumulae's out there for gaining mass. However I've found that very few actually get my maintainence requirements right but I tend to know what that point is. Not in actual numbers but in terms of food quantity or overall fullness.
Hope that ramblings answered at least one question you asked.
