But you can't get that far unless you understand the basic principles of hyphenation: Sometimes you use them to connect words, especially when creating modifiers: smooth-talking salesman. But sometimes hyphens are officially included in the spelling of a word.
In addition to knowing when to look things up, we "experts" have some special insight on where to look things up. Sometimes answers are in the dictionary, but other times we rely on our arsenals of style guides such as "The Chicago Manual of Style" and the "Associated Press Stylebook," or usage guides such as "Garner's Modern American Usage" and "The New Fowler's Modern English Usage."
Here you'll find not rules but guidelines and expert judgment calls on just about any question you might anticipate, including this little gem Ted found in "Chicago:" "regrettable; regretful. What is regrettable is unfortunate or deplorable. A person who is regretful feels regret or sorrow for something done or lost. The adverb 'regrettably,' not 'regretfully,' is the synonym of 'unfortunately.'"