The secret to getting a nice horizontal bow - on your shoe or neck - as opposed to a wonky or clown-like vertical bow, is quite simple - treat it like a bow tie...
Well...that's if you already know how to tie a proper bow tie. If you don't, instructions are provided here for practice.
Start with the basics: the end of the lace (or tie) in your LEFT hand (as you look down at your shoes or yourself in the mirror) should be pointing UP after the first loop over (Illustration 3.). See the handy Bow Tying Guide here:
The image in illustration (3.) is the exact process you should employ when tying your shoe laces.
Finish the process as you normally would to make your bow and the results will be a game-changing, perfectly horizontal bow. Simple.