If you are physically moving the tested site to another server, then take a look at the guidelines here. You can however selectively use the information you need from this to switch from dev to live
The main things to remember when doing this are the following
If you are converting the other system, do a test first. This will save you having issues on the day you do it for real, and you will know what to expect
Use -TESTINSTALL at the end of your license key, to use your test key instance. That way you dont have any issues with switching to your live domain. You just move it and set your live license key
Any issues at all, go to ACP->Support (top right) and see that page to see if there is anything showing up, and (as already mentioned) use clear cache
Make sure if you are moving from a subfolder, you change any .htaccess files (and indeed ensure you move that, as I have seen people miss that where its hidden)
When changing your conf_global.php file, back it up, then change it. That way if you make a mistake, you can repeat that process. I have seen many times someone accidentally delete or add something that breaks the site on moving items
One thing you can do to speed up the process, is if you are moving from one location to another with the physical files, make a copy of all the files in advance. Then you can just replace those which have been added or changed.