Transfer all of the content over first. Make sure it's up and running before you make the nameserver switch that way there's no downtime.

Depending on the site, it's fairly easy to transfer. Your new host should be able to take care of this. Not all hosts will transfer TO cPanel if your old host doesn't have cPanel.


Switching hosts shouldn't have an affect on anything. I'm sure the SEO hosting lovers will be here shortly to tell you otherwise.

Yeah no affect on seo . if new hosting provide same quality. Most hosting providers provide all transfering of your data from old to new.