Ok I have no in the process pictures, but the descriptions should be clear without them. My english isn't so polished so feel free to ask if you don't understand something.
Paint your nails the background color(lighter one, obviously)
*Mine was OPI's quick drying silver(I don't know the name because it's pretty old)*
Cut the tape to have lots of stripes of your desirable width and put it somewhere, where you can reach and take them off easily(f.e. one side of the stripe is on the edge of the table and the other is in the air)
*Mine were about 3 mm's and about 15 stripes for one hand*
Place the stripes on your nails(I suggest doing one hand at a time and let it dry before doing another). Leave just about the same width you cut your stripes in in-between them.(You may vary the widths of course to create new designs)
Make sure to press them good at the corners of your nails. Also, I suggest leaving longer stripes for a more comfortable way to remove them.
Paint on the darker polish. I suggest not putting it harshly all over the nail. I just brushed it through the un-taped lines.
*Mine was AVON's matte black. All other black nail polishes of mine are either too old to work or finished*
Wait for the polish to dry and be very careful while taking of the tape.
Now there's a great chance that you see all kinds of imperfections and sh*t. Don't worry - fix them with a brush.
Wait to COMPLETELY dry.
Put on the top coat.
And go out to celebrate your new nails!