I've got a simple tutorial for you.
Sleek striped nail art.
You will need to paint your nails one color and let it dry completely. Then you'll want to get some tape. You can use scotch tape, but I prefer painter's tape.
Pick another color that you want to go with what is already on your nails.
Now let's do this!
I suggest doing one entire hand at a time. Then letting that hand dry... and follow-up by doing your other hand. This will decrease your odds of smudges.
After you have painted ALL of your nails on that hand you can remove the tape to reveal the stripes.
And there you go! Think of all the cool color combinations you could do with this!
Try it out and let me know how yours turn out. Also if you have any nail art / tutorial requests just let me know in the comments.
Happy painting to you!