I recently learned that the construction +かける means to start something, but with an implication that the action was left unfinished:
"I've had a beer before, but I didn't like its taste at all." (かけた here tells us I did not finish the beer.)
But I've also learned that in certain cases, there is no such implication of something being left unfinished:
"I have gradually started to understand his feelings."
(This example is from maggiesensei.com)
How can I tell when a sense of incompletion is implied? Not knowing this could lead to some confusion and poor translation.