Many people especially the highly educated and rational thinkers "believes" astrology to be superstition. Many rationalists asks me to "scientifically prove" that astrology works or accept that it is just a tool to fool gullible people.
I am sure you would have had doubts or met with such challenges in your life as well.
One of the best way to deal is ask a counter question to "Prove" that astrology does not work. And the proof has to be in the same way as they expect from me.
Most "rationalist" simply say - How can planet revolving thousands mile away can affect my life? Now this is not a "proof" of anything. This is just an "assumption" that astrology doesn't work. It proves nothing.
The most rational approach to anyone who is new and doubtful towards astrology is that of an agnostic i.e. I don't know whether astrology works or not. And unless the "rationalist" challenging me to prove astrology can at least agree to this fact; I usually just don't discuss anything further.