All great info, which I won't repeat. The next trick is actually predicting the waves, which I find to be the least accurate of all weather forecasts. Start by checking NOAA weather buoys online, if you can. There are smart phone apps and websites. Then check forecasts, like passage weather or the like, but look at the trend from a day before to day after. The only thing I've come to believe is, if the forecast says they are building, they will. What they may build to is a mystery, but at least you can check current conditions and understand whether they should be going up or down.
Generally, the worst waves are caused by opposing wind direction and current direction. Wind can oppose a major ocean current or tidal current and get nasty. While sustained winds that come from shore don't typically travel far enough over coastal water to kick up big waves, they are nasty if there is swell heading toward shore from a long away storm system. Lots and lots of variables.
So, a final rule of thumb. If its just my wife and I, we are hardened enough to take some seas we would never sail guests into. That said, when on vacation, if we start to see anything over 6 ft on a coastal cruise, it's usually being caused by a storm or high winds that are just going to make it unpleasant. We will do it when necessary, meaning there are no bars open wherever we are at the moment
I've never been on a cruising vacation, where I haven't stayed hunkered down at least once. If you can predict the tougher conditions out a couple of days, adjust your schedule to be somewhere you don't mind staying over.