First thing to check is did you enable "Rotating Minimap" in your interface options?
Basically what this does is make sure the map rotates around you so your arrow always points north like my screenshot.

This means you can then use the mini cords, if you don't enable this you could be trying to target behind you = not in line of sight.

Additionally try starting with +1 on vertical only, this is a good way to see how it works and then improve on it.