WB4AIO offers some excellent information and I would like to add the
following:

Generally speaking, (Note I stated GENERALLY SPEAKING here) end fed antennas
tend to be most directional in line with their longitudinal axis. In other
words, an inverted-L, end fed, would pick up the greatest
capture in the direction that it is "pointing."

Center fed antennas GENERALLY tend to be most directional perpendicular to
their
longitudinal axis.

Again, I stress these are VERY BROAD and GENERAL rules of thumb. Of course
there
are always exceptions such as the center fed Zepp which tends to be most
directive off its
ends. As one respondent stated...experiment. There is a reason they call
technical suppositions "theories."
It is because they are just that, theories only. Real world performance is
whatever you get and can be
morphed by ground conductivity, nearby structures, interactions and terrain
as well as theories that are conventional but one day will be refuted.