Open qualifier greens are set at "Tournament 1" or Tour Master speed. Having said that, the greens generally play "Very Fast" uphill and "Championship" downhill. For this reason, as a general rule, you must figure out for each hole where to 'miss'. If you can throw darts to a couple feet from pin, it isn't an issue. However being 4 feet above a hole can lead to a frustrating bogey. Below the hole - that's Olympic strategy Number 1.
Next, the trees issue is very real on a number of holes. Full backspin, topspin, no spin, each of these 'tree' driving holes is an art form to be learned, and since most play to influential side winds, these must be taken into account.
Also, a number of holes are much easier with a 3 wood than a driver - since being on the fairway is absolutely at a premium; I would calculate that 90% of the rough on Olympic is of the "40/50" variety, even just off the fairway or just off the green. If you miss the fairway, its a struggle for par, period. Very few birdies are to be had from the rough unless you manage a pitch in from off the green.
Further, the greens are not all mapped perfectly. The dots simply lie in many cases. This is a learned skill, much like on Kiawah.
The Open qualifier, unlimited play, is a great way to learn the ropes- I have played plenty of times, quitting on 18, and re-starting. I also have been playing Olympic almost exclusively in Alt Shot matches, to continue to learn the nuances, where to miss and where not to miss, and sometimes another player in the match will show you how to get it done you had not considered before.
Its a very tough course, set to tough conditions. The good news: it makes even Oakmont seem a lot easier!