If your ends are stringy, they may need to be cut. It may be damage, to many layers, or terminal length. I feel most cuts look best with some weight at the bottom.
As for the root lift, it can be tricky on longer, finer hair.
Leaving enough weight at the bottom, but taking the weight out at the top. I have a few ways I can do this. Rounding out the layers, leaving weight in the middles. Or I can get creative and pick up strategic curls at the crown where you want the lift and cut them a few more c's then the rest. This kind of cut must be styled and cliped to the cut to work properly. Careful, this is also where some feel a deva cut is uneven. hth