Depending on your locale (upstairs, downstairs), use 90° orientation for current floor, 0° for upstairs, downstairs, and 45° for upstairs/downstairs, a bit displaced from where the AP is sitting.
Have at least two in 90° position. It affects the polarization of the radiowaves, and it's often helpful to mix this up. Laptops usually have two small patch antennas which sit at the top and side of the screen, one oriented vertically and one horizontally. If you need to cover one direction only, place a large copper plate/mesh on the opposite side of the direction you want to cover. It will reflect. You can also use wallpaper/paint infused with metal particles to get better coverage (a bouncy cage), and reduce interference from unwanted 2.4GHz sources.
For longer ranges, use bigger omnis, or patch antennas. I have found big omnis and patch antennas to be a lot more useful than e.g. parabolics, which are only useful for point-to-point links.