It depends on how the devel environment is setup.

If the devel server is the same server as the "live" server and you just have the DNS setup as an internal pointer then you can just switch the DNS and you're good to go - as it will be the exact same environment.

If the site is on a different devel server or a local server, you'll first want to upload it to the live server and setup a temporary DNS pointer so you can make config changes and make sure it's all working before you switch it on.

If the site isn't already live (no traffic or rankings) just upload the files as you normally would and change the config so it's working properly - there's no rush if the site isn't already live and no need to complicate things.

The easiest way I know of moving a WordPress site is to use BackupBuddy. It will back up the entire site (database and files) and you can then install the site on a different server and domain if necessary, following the steps on the screen. BackupBuddy is a paid plugin but absolutely worth the investment.

You say the site already has top rankings and traffic - does that mean that a current version of the site is already on the domain, which is not changing, and that you're converting it from a static site to a WordPress based site (which is what you built on the development server)..?

If so, you will need to set up permanent redirects from the old URLS to the new ones, because the WordPress permalinks will be different from the URLs of the pages on the current site.

More info on converting a site to WordPress here:

Migrate an HTML Website to WordPress | WealthyDragon

Cheers,

Martin.

There is the hard way and the easy way.
Step 1
The hard way is to export the database, then set up a new one in the live site cpanel then import the database.

Step 2
set up ftp and upload all your files check your site is working, you may need to do tweaking both on the site setting and in the mysql database depending on how you set it up.

Step 3 go to tools export posts/pages, upload the files, set up the import plugin and import everything. It should be working.

You may need to change your database name and also your config php file. doing the edits in the database can be tricky if you don't know where to look and you need to do them. Depending on how you set it up, the database might call your loacal host and the site won't work until you set teh database to call the online address.

The easy was buy backup buddy and run.
***When you set up the cloned site you will need access to the cpanel or the database prefix, the import will not work unless you have that. Other than that it is easy and straight forward.
And you will need to set up the database manually to install it. If you don’t want to do that manually it can be done with WP-DBManager and Portable phpMyAdmin

Sometimes it puts a blank html file there and the site does not show. DON’T PANIC! Rename the index file to .bak just in case it is something else and refresh your site.

All good.
Good luck
You can also try wp-twin it probably a bit easier as you don’t need to set up the database it does that for you, but generally it won’t work on your localhost environment so it’s probably the worst option

Read more about data migration... as long as you have backup, you don't have to worry. You can do it, first you need the database back of the site, and all the backup files. Maybe your using a client server. I can't list down here what you really need to do because you didn't mention the server your handling/working.

Carin,

First I want to say that Carin asked for help and does not need to be scolded. I am sure that everyone who has worked with WordPress has made their share of mistakes too!

The person who recommended Backup Buddy is absolutely right. I have used it many times and it always works for me.

I build WordPress websites on my local development machine and use Backup Buddy to back them up, and move them, which takes no more than a 15 minutes.

I FTP the backup to the destination server, go to cPanel and create a database, a dBuser and execute the install script in my browser. You really can move the entire site in 10 to 15 minutes or less.

If you are installing to the same domain name you will not have to worry about redirects but as someone else mentioned if the domain name is different and you are already getting traffic that you do not want to lose you will have to leave 301 redirects in place on the old server for each page on the old server.

The company who sells Backup Buddy is ithemes.com

Good Luck!