The job should be simple enough. Screw the two vertical tracks to the wall, snug some brackets into the tracks, and put shelves on the brackets. Of course, you want the tracks to be plumb and level with each other. Otherwise, the shelves will be cockeyed, and stuff will start sliding off. That's where it gets tricky. The traditional way to make sure everything lines up is with a standard 4' level, the way it's been done for hundreds of years, and the way I've always done it in the past. It works just fine, except, it's awkward when you're working by yourself. You always need to figure out how to hold the level in proper position whilst you're doing whatever it is you need to do, an operation that frequently wants for a couple three extra arms. Usually you wind up putting up one piece, then propping one end of the level on that while adjusting the other end, taking into account any offset, trying to put the other piece into place, hoping the whole thing doesn't fall, and damnit, the frelling drill is out of reach. Bother.
The other problem with a standard level is that it's only 4' long (usually). If you're planning on doing something longer than that you need to make more than one measurement, with the associated risk of having otherwise minor errors in measurement start to combine into something substantial. Consider the case on putting up three vertical tracks to hold the brackets for some longer shelves. You use your level to make sure that the left and middle tracks line up, and then again for the middle and right tracks, and everything is just dandy until you notice that despite everything, the middle track is 1/8" higher than the two outer tracks. If there were only two tracks, you'd probably never notice the difference. However, since your shelves are now seesawing on the middle brackets, that teeny error becomes all too apparent.
One way of handling long lengths it to grab a long straight something or other (usually a length of wood), and put the level on top of that. Needless to say, that can be even more awkward, especially by yourself, and sometimes finding a nice straight piece of wood is harder than it seems. Another option is a water level, which is simply a long piece of transparent tubing filled with water. Since water is self-leveling, the height of the water at each end of the tube will be the same. If you need a line, you snap a chalk line between the two ends. Neat, but it's still awkward, now you've got chalk on the wall, and it's really messy if you accidentally drop one of the ends (and what are the odds of that happening?).
So, what does a mad scientist do when he needs to improve a tool? Easy. He adds a laser beam to it. Take a laser pointer, put a beam spreader on the end to turn the laser line into a laser plane, and attach that sucker to a level. What it does is make a chalk line without any chalk. Theoretically, the line is perfectly level across the surface. What happens in practice is another matter.
There are several types available. The first one I bought is a standard torpedo level with a laser in one end that projects a line parallel to the level. The main reason I picked it is that it's still a perfectly good level even if the batteries are dead, and it came with a teeny little tripod that would also work with my digital camera. Multitasking, and the whole shebang was only $15. The way you use it is to set it on the tripod in the center of the room at the desired height, level it using the bubble on the level, and turn it on. There should now be a perfectly level line on the wall(s) you pointed it at. Except, there's a catch.
Picture a metal frosting spatula, or a putty knife. The handle is the level, and the blade is the laser beam. The bubble on the level runs front to back, and is great for aligning the handle of the spatula (and thus the beam) parallel to the ground front to back. That does not mean the blade is necessarily parallel side to side. If the level is tilted even a tiny bit, the beam that reaches the wall will only be at the right height at the very center. Try as I might I never was able able to get a level line on the wall (I used a standard level to check it). I even switched from the teeny level to my camcorder tripod, which has not one, but two centering bubbles on it. I even put another centering bubble on top of the whole thing. Still no dice. It only needs to be tilted by a hair to throw things way off. Meanwhile, I discovered another problem. I wanted my line up near the ceiling, because it's easier to hang shelf tracks from the top down than the bottom up. That made it very difficult to get my head in a position to see the centering bubble, let alone make adjustments. Feh. I tried a couple more arrangements, but I wasn't able to get a good level line. Time to try another approach.
There's another type of laser level where the beam and bubble assembly are mounted on a base that swivels. The idea here is that you attach the base directly to the wall at the desired height, and then swivel the beam until the bubble is level. This takes the whole tilt factor right out of the equation. Heck of an idea. (I tried doing this with the torpedo level, but didn't have a good way of attaching the level to the wall in a way that would make it swivelable.) I had to go to the Depot anyway, and I had a gift card, so why not? There are several attachment systems. Suction bases are expensive. Some use gripping claws, which after I just spackled and painted the walls? I don't think so. The one I bought used special double-sided tape strips that actually work as advertised. Sadly, that was the only thing that worked well.
I put the batteries in, slapped a tape strip on the back, stuck it to the wall, and turned it on. Swiveling it until the bubble said it was level was a piece o'cake. Just to be sure, I checked it with a standard level. It was off by about ½" over only 4'. I had to swivel so the bubble actually touched one of the guide lines to get the line level. The beam and bubble weren't aligned correctly. Nothing to be done about it. I took it off the wall, and stuffed it back in its packaging. I'll return it tonight. Even if they were, the bubble on this particular level might be too small to get the beam precisely level. I'm not sure I want to spend any more money trying others.
Needless to say, I'm disappointed that technology failed me so. What I might do is try to fashion some sort of swivel for the torpedo level out of some hardwood. That might be the best of both worlds. I can buy those snazzy tape strips (the one piece of technology that actually worked) separately, so that might just work.
In other tech news, I'm trying to set up an appointment at the dealer to have the bad u-joint on my truck replaced, but the service department has a message on their system that says my call back may be delayed because too many people are on vacation this week.