Most English Dictionaries have syllable divisions, that is, you can see the word definition and the word divided by dots (which indicate said division).http://michaelis.uol.com.br/escolar/ing ... attractive
This one uses (-) hyphens, though.http://www.howmanysyllables.com/words/attractive
A rule of thumb is that a word with a sound, like "attractive" in wich there´s just one t-sound (and consonantal) you break one of the consonants.
Some other rules:http://dictionary2.classic.reference.co ... ision.html
By looking up the words in a dictionary you can´t be wrong, with time you get used to the separation of syllables.
On the English Experts site some word may have it´s parts broken non-grammatically, that´s happen because of the program in wich it uses, so don´t worry about it. At least in the EE site, I mean.