Before moving your hosting take a backup of everything you can and do not forget your database if your site relies on it.

If you are moving to a host who has as different control panel, make a manual backup by downloading all your files because different control panels may not be able to restore the backups made by your old host. They also have different directory structures.

If server logs are important for you then please remember to backup those too. There is no good way of moving logs yet because different hosts may log statistics differently. So the best thing to do is to download it your computer to make references to later on.

Gather Odds & Ends

1. A Good FTP program which you should have.
2. Get your new host server's DNS
3. Get the temporary URL on your new host so you can check your site before you make a DNS change.
4. If you have your host control the domain inform them not to change your DNS until you tell them to.

Inform Your Visitors

It is common and good practice to inform your visitors and customers of the server move. This helps assure your customers you have not fled with their money if there is any downtime.

Moving Day

Try to schedule the move at a time where there is least traffic. Backup again just before you do the move so you will have the latest data. Start by first copying or creating your custom error pages onto the new host server. Put a small note in there about the move. You can always remove it later. Then upload the most visible parts of the site first i.e the main pages then move on to the less critical parts of the site. If you have a large site with many divisions you might want to split them across different days and instead move the least critical first. Just ensure you always do a backup before you do any moving. Use the temporary URL to check your site, visiting as many pages as you can.

Changing DNS

Once you are satisfied, change your DNS over. This typically takes about 24-48 hours so you have time to make some minor changes if need be. You might want to also take this time to modify your old site's error pages to inform your visitors of the move and give a new URL if there are URL changes.

Monitor

After you have moved and the DNS resolved, do not release the old account yet. Keep it as long as two weeks running concurrently. Go back and check the old servers for activity. Check your old email account and if you have a web based contact method on the old server check to see if any communication is left there. Once you are comfortable all email and traffic is correctly directed to the new host server, you can cancel that account.