I usually just click around until I can find a good big space, usually takes a few times of starting over. But I have never been able to beat this on expert mode without having to at least guess once, maybe it's just my luck, but it seems to me that it will always make you guess, and that is what usually gets me.
There are definitely times where you have to guess, but I'd say only about 20% of the times you play Expert is that the case. I can just about always beat Expert if I take my time, but if I'm going for a record, I guess a few times at least. The difference is, after a while, you start to notice patterns, which make the guesses only half guesses in essence.