Hope you have a great time at Cedar Point and Kings Island. Assume you may have a pass already, but if you don't, you might want to consider getting a Platinum pass. It will get you into both parks, and is usually cheaper after a few park days than paying for general admission.
Both parks are huge, but because CP is on the peninsula, there is a lot of walking involved given it's one long, narrow piece of land. Obviously the big coasters are the stars in both parks. So choosing your plan of attack in advance is good. Evaluate those coasters (such as a B&M) that usually have good ride capacity and can cycle trains through quickly versus those that may have slower moving lines. If you can afford it, Fast Lane is great to assure that you get on as many things as you want.
Another tip, good for most parks if you're not already aware, is to walk past all the coasters that are in the front of the park. That would mean skipping Raptor, GateKeeper, and Valravn and heading back to others. The average folks come into the park, see a ride, and head to it. So usually those coasters and rides in the front are busy while other parts are not. Not sure how much Steel Vengeance changed that pattern as I haven't been yet since it opened.
For CP, it's great to stay onsite at one of their properties. That makes it easy to come and go from the park and means you don't have to deal with daily parking (and fee). But the CP properties are pricey compared to others nearby, so it's a trade off. At KI, there really isn't a lot that is preferred to other locations, so just find something on either side of the interstate that fits your price and quality choices. You're likely going to drive and park anyway. And if you have the aforementioned Platinum pass, then you won't be paying for parking anyway.
Without knowing some more specific questions that you might have, it's hard to chime in otherwise. Hope this at least helps some. Have a great time!