Good advice to you- as I was in a technology magnet program at my highschool, is to actually go about the project as a true project. Document everything from research: pros and cons to products you purchased and why. I can easily put in 15hrs just in research of parts, reading reviews, tests and comparisons. Plan how you want to route the cables and make it look neat. What a lot of people miss or overlook with computers is how they work. People take them for granted, and its those who may not know how to build a computer are the ones who pay someone to repair them. Knowledge is the first step to doing something on your own.
Case modding is surprisingly easy. Its easiest to- like always make a plan. Do a 3D sketch of what you want the case to look like. Google sketchup is great for this (free). Then more research goes into how to go about the mod- from materials to use, how to fabricate the pieces and mount things. Again all research and planning can easily take up the 15hours. With my current work log, I played with my 3D design for hours on end figuring what else to do/add. You see your plan develop and when you work on it, its amazing to see it resemble your original design.
Its as easy as using a dremel to cut out some holes for wires to feed through to make it look neater.
OCN is a great resource for information- both personal experiences,research from members and links we post. Read through threads and also read the stickies in the overclocking threads, great walkthroughs there! I didnt know anything about overclocking, but its a trial and error process. My advice is do one thing at a time and see/document the effect it had. Dont go changing, RAM frequencies, Hypertransport speed, cpu speed, and voltages. You dont know which might have caused your computer to crash/reboot.
I wish you best of luck, and hope that what I said is helpful in any way. Feel free to ask questions in other threads too.