All you do is first, paint your nail like normal. Once dry cover all the parts of the nail (that you want to keep this original color) with your Scotch Tape.
Then with your second coat repaint your nails. Once their dry remove the tape and wam bam thank you ma'am you have some cute looking nails! Doing this saves you the time and money you would have put towards the salon, that you can now put towards studying! Or shopping, i like shopping.