personally i don't believe the planets have a direct influence but instead they have strong correlations with certain patterns. and over thousands of years, humans have learned to interpret these patterns in ways that can be used for prediction.

e.g mercury retrograde = communication/travel/technology difficulties. i don't think the planet itself is affecting these things, but it happens so often that i can comfortably say "when mercury retrogrades, i expect some piece of tech will break or i'll run into travel delays". and then it happens, but instead of being upset or angry i think "wow, i saw this coming! very cool (:"

that was a basic example but anyway here's my collection of thoughts/research