So how do you tell if an anime is eyegasm fantastic or going to turn into a load of crap that a monkey wouldn't even throw at their worst enemy?
Simple...apologies to the female of our species but this is just how it is...
Story +/- quality of characters - (Breast size of characters X number of times they emphasize that size + number of times in one episode someone gets groped or they talk about ecchi topics) = quality level of the anime you will expect to find.
Note, there are rare exceptions to those rules, but most of the time the bigger the top or the more they emphasize characters obsessed with them, the lower quality you'll find. Ai Yori Aoshi is a perfect example of a fantastic show ruined by one crude character. If her character was cut out entirely, the show would have been much better.