Some excellent suggestions given already, but I would definitely encourage you to take the advice to find several (3-6) AWESOME holes. The type that people dream about playing -- a few of those holes will keep people coming back no matter what the course looks like.
Also, I would consider as many as three teepads for each hole if you can -- heavily wooded courses can benefit tremendously from this, since just changing a teepad by a few feet can totally change the lines available to the basket. Have the short teepads be short (180'-250' for most holes, with a couple of "long" 330' shots), so novice players will stay interested. Then the second, intermediate teepads should be back probably another 50' on average. Then for the third set of teepads, ever hole doesn't necessarily have to be any longer, but the routes should be more demanding -- think about tighter gaps off the box, forced doglegs that require placement shots, big anhyzer/flick lines, maybe even a forced hammer/thumber/grenade or two, depending on what fits the hole. I'd also make sure that the hardest teeboxes have at least two or three longer holes -- true par 5s if possible. This way your course will appeal to all skill levels -- from the novice to the masochist.
The other thing to try to work in, if possible, is at least ONE hole that is open so that people can really rip their drives. I don't know if you have any field space at all in your 30 acres, but I've noticed that courses with ZERO open holes can feel a little claustrophobic for many people. But if there is even one hole where you can open up and let your arm loose, that will help tremendously -- it gives players a place to practice a totally different kind of shot, and is a hole they can look forward to. Ideally, that open hole would be at least 450' of field from the longest teebox, so that all players have space to really bomb their drives. The pin should probably be back in the trees another 50-80' or so, requiring that placement is more important than pure distance from a strategy perspective, but again, just having that space to rip a full strength drive will help immensely in having players enjoy the course. It's a great stress reliever. In a perfect world, I think hole 9 or 10 on the course would be the field hole, since that's mid round and gives people a mental break and a chance to vent their frustration from all the trees they hit on the first half the course.
The other things to consider: since this will be a private course, where will people park? If you are going to host tournaments, is there ample parking space somewhere? Camping space? (not sure what your final goals are for the land). I've seen several private courses be designed great as long as only 2-3 cars show up to play, but once they start thinking about a tourney, they have to redesign a couple of holes to give people a place to put their cars.
The water ideas are awesome if you can use them -- a peninsula would be really sweet, but also great are shots that force you to put a hyzer or anhyzer out over the water to a basket a little way around the shore -- again, the risk/reward element.
Last thing to consider and keep in mind as you are playing: prevailing winds. Usually, wooded courses aren't too windy, but if you're putting a few holes in the open -- especially around open water -- think about where the wind is usually coming from and how that might affect shots. If a hole out over a lake is always going to be upwind, be kind and make it a little shorter, so people don't get too frustrated and keep losing discs.
Last thing (I promise): make sure that whatever elevation you have is used well and often -- courses that maximize elevation often have the most interest to play. More thoughts to come later on what to do with the elevation you've got, but for now, while you are walking the course, just pay attention to where it is and how to use it. Also, a key part of elevation is paying attention to any low/swampy areas and trying to keep those away from tees/pins/fairways. It's fine to have swampy areas as the rough, but awful to have to hike through a swamp when you had a great drive. So think about how the land drains throughout the year -- courses designed in dry seasons sometimes turn nasty in the spring rain...
Sounds like you've got you're work cut out for you, but I wish you well. I'm jealous. I -- like almost every other disc golfer here -- have always dreamed of designing a course.