Operating systems have traditionally been installed from disc (or disk, if we're looking back that far), but Apple decided to change that with Lion. That comes with some benefits, but as with most firsts it also comes with a lot of buggy problems. Here's how to fix some of the most common.
Got a Boot Camp Partition?
If you do, you might be receiving a message telling you "This disk cannot be used to start up your computer". Well, of course it can, but Lion's just being annoying. To fix it, you just open up Disk Utility (Hard Drive -> Applications -> Utilities), choose your hard drive, click the Partition tab, and resize your Mac partition to be 128MB smaller. Click Apply and you should now be able to install Lion without issue. (You can resize it back when you're done, too.) For the fully-illustrated instructions, head on over to Apple's support site.
Got a Hackintosh?
We've got the full installation instructions, but maybe you've run into a few problems that weren't covered. Because there are so many more variables with Hackintoshes and their hardware, it's hard to pinpoint them all. That said, there are a few things you should be aware of.
First, if you have a dual monitor setup, reduce it to a single display for the entire installation. While Lion will support multiple displays with some graphics cards, it can cause problems. You'll also want to unplug any peripherals that aren't needed if you're running into issues. If you have multiple drives in your system, make sure you create the Lion "Installer" partition on your boot drive.
While you should be able to get away with using another drive - even an external - you're tempting fate by doing so. If those things don't work, you may want to wait for tonymacx86 to update his xMove utility. Alternatively, if xMove isn't working for you, maybe Kakewalk will.
Getting Kernel Panics?
If you're plagued by kernel panics post-installation, MacLife recommends performing routine maintenance like clearing caches and repairing disk permissions. Disk permission repair can be performed easily with Disk Utility (Hard Drive -> Applications -> Utilities), but you might want to check out Lion Cache Cleaner to handle the other tasks.