I would not advice you to search for tips on how to clean registry unless you intend to make use of registry cleaning tools. Trying to find out how to clean registry manually does not make any sense whatsoever.

For starters, the registry is too big to be edited and cleaned up without any automation. Knowing how to clean registry is one thing. However, going ahead and actually cleaning the obsolete keys and values in the registry is totally different thing. It will not be very difficult for a person having knowledge of computer language and computer operating systems to differentiate between a necessary and an unnecessary key in the registry. With a bit of help from the web in the form of tips on how to clean registry, one can, at least in theory, clean the registry without any help.

However, this will not work because the registry is just too big to be cleaned by a single person. One cannot make use of a team of persons just to find out how to clean registry manually. Unless you are an eccentric multi billionaire feeling bored, just drop the idea of cleaning the registry manually.

Just opt for a registry cleaning program instead. These programs are very simple to run. You do not have to be a computer software expert to use these programs. Further, most programs take a backup of the registry so that you can restore your OS to normalcy if something goes wrong during the cleanup.