There are lots of tools that making nursing easier, but only two must haves on my list - nursing tank tops (the ones that clip down at each spaghetti strap, get at least 3-5) and nursing pads (my favorite are reusable soft cloth pads but disposable are useful for on the go). Switch out the nursing pads often because moisture against your skin can cause irritation or worse, infection.
Remember that every baby is different when it comes to how much milk (and later food) they need. With my first two babies, I was constantly worried about whether they were getting enough milk. I even bought a baby scale to keep track of how many ounces they were taking with each feeding! Their pediatrician assured me that they were getting what they needed but they were both so skinny and always on the very lowest end of the weight scale - 5th or 10th percentile. I tried everything to bring up their weight - formula to supplement and constant long feedings on both sides, to no avail. Then I had my third, a ravenous baby boy. Without me having to put in any special effort, he loves to nurse and eat and put on weight easily, always weighing in at the 80th percentile or higher. I realized that when it came to nursing, I didn't do anything different with the three of them, but each baby is unique and has different needs to be healthy. By the way, my older girls are now 8 and 6 and STILL not big eaters, but they are both strong and energetic and hike 2-3 miles up mountains without breaking a sweat!