Softening the springs may or may not make it corner better. You will get more body roll if the springs are softer, which will hurt your cornering, but with the softer setup your tires will have more constant contact with the ground which will help if the corners are rough or uneven. It won't hurt to play around with the settings, and it is fairly easy to do, and the only tool you really need is a pair of channel lock pliers to adjust the front (the rear preload is quite a bit more time consuming to adjust)
First, I like to lift the front tires off the ground to take the weight off the springs. I use an old computer and just sit the front of the frame on top of that, but you can really use anything, like a floor jack, milk crate, etc. Then simply use the pliers to grip the preload collar on the bottom of the shock, and twist the collar so the peg sits in a different notch. The lower the notch is, the softer the spring will be. You can grip onto the knurled part of the collar, or the smooth part, whichever works best for you. I think the smooth part of the collar works a little better, but either way should work just fine.