It’s photo 101, but many landscape photographers are unaware of it. The horizon tends to look best when it doesn’t split the center of the image. Of course there are exceptions to every rule, but unless you can articulate with specificity why you want to do it differently, avoid putting the horizon dead center. You can put the horizon toward the top or the bottom of the screen. Either way is acceptable and both are traditionally more pleasing to the eye than putting the horizon dead center.
While we’re talking horizons here is a bonus tip. Make sure your horizon is level. Even inexpensive DSLRs now come with built-in levels so there’s no excuse not to get a level horizon. If you still mess that up, crop it in post so it is level for a more pleasing photo. _______________